Technical Field
[0001] The present invention relates to a novel bisphosphine ligand having a cyclopentane
structure and a novel catalyst comprising the ligand and a transition metal, and also
to the use of the catalyst.
Background Art
[0002] Many agents such as medicaments and agricultural chemicals utilizing an optically
active compound as an active ingredient are known. A number of methods are known as
methods for preparing optically active compounds. Among them, the catalytic asymmetric
synthesis technique is one of extremely powerful means. Since transition metal complexes
having optically active phosphine as a ligand have superior catalytic activity and
stereoselectivity for the catalytic asymmetric synthesis, they are also applied to
industrial manufacturing processes (
CATALYTIC ASYMMETRIC SYNTHESIS, Ed., Iwao Ojima, Wiley-VCH, 2000).
[0003] As optically active ligands which can form asymmetric catalysts, phosphine ligands
and phosphorane ligands are known. As the phosphine ligands, for example, BPPM, BINAP,
DIOP and the like are known, and as the phosphorane ligands, DuPHOS, BPE and the like
are known. Although many of the phosphine ligands except for BINAP can be used for
asymmetric hydrogenation of acetamidoacrylates, many of the ligands have rather narrower
applicable range for other substrates. Moreover, they have problems in industrial
application, for example, the synthetic route is long and each enantiomer cannot be
obtained easily. The phosphorane ligands are reported to have characteristics not
possessed by the conventional phosphine ligands, and to be excellent asymmetric hydrogenation
catalysts (
WO93/01199 (DuPHOS),
WO91/17998 (BPE)). However, in order to form a phosphorane ring, an expensive optically active 1,3-
or 1,4-diol is needed, and in addition, Et-DuPHOS, Et-BPE, Me-BPE and the like are
oily substances and therefore have problems of susceptibility to oxidization and difficulty
in handling.

(In the formulas, Me represents methyl group, and Et represents ethyl group.)
[0004] It is reported by Achiwa et al. that the phosphine ligand, PPCP, having a cyclopentane
structure and forming a 6-membered ring chelate is fixed in the Skew arrangement and
has superior stereoselectivity (
Synlett, 49, 1991). However, it is difficult to modify the cyclopentane structure in the synthetic
route in which a beta-ketoester compound is asymmetrically reduced with BINAP-Ru,
and the resultant ester is reduced with a hydride. It is not easy to design and use
an suitable ligand depending on a given substrate.
[0005] Although a catalyst having a cyclopentane structure is also disclosed in
EP 1595 885 A2, the asymmetric hydrogenation reaction characteristic to the present invention is
not described.
Disclosure of the Invention
Object to be Achieved by the Invention
[0006] An object of the present invention is to provide an optically active phosphine ligand
which can be easily synthesized and provides a transition metal complex superior in
asymmetric catalyst activity. Another object of the present invention is to provide
an optically active ligand which has a chemical structure easily synthesizable by
choosing suitable substituents depending on a substrate, and either or both enantiomers
of which ligand is readily synthesizable.
Means for Achieving the Object
[0007] The inventors of the present invention conducted various researches in order to achieve
the foregoing objects. As a result, they found that the compounds represented by the
following general formula (I) were easily synthesizable and had extremely superior
features as a ligand for providing a transition metal complex superior in asymmetric
catalyst activity, and accomplished the present invention.
[0008] The present invention thus provides a compound represented by the following general
formula (I):

[wherein R
1 represents hydrogen atom, or an alkyl group, R
2 represents a hydroxyalkyl group, or a triarylmethyloxyalkyl group, or R
1 and R
2 combine together to represent - C(R
3)(R
4)- (R
3 and R
4 independently represent hydrogen atom, a linear, branched or cyclic alkyl group,
or hydroxyl group, or R
3 and R
4 may combine together to represent oxo group), or - C(R
5)(R
6)-O-C(R
7)(R
8)- (R
5, R
6, R
7 and R
8 independently represent hydrogen atom, a linear, branched or cyclic alkyl group,
or hydroxyl group, or R
5 and R
6 may combine together to represent oxo group, and/or R
7 and R
8 may combine together to represent oxo group); Ar
1, Ar
2, Ar
3 and Ar
4 independently represent an aryl group (the aryl group may have 1 to 5 of the same
or different substituents selected from the group consisting of hydroxyl group, alkyl
group, alkoxyl group, amino group, alkyl amino group, nitro group, cyano group, aryl
group, halogen atom), *1, *2, *3 and *4 indicate asymmetric carbons, and relative
steric configurations thereof are in cis-configuration between *1 and *2, cis-configuration
between *3 and *4, and trans-configuration between *2 and *3].
[0009] According to preferred embodiments of the aforementioned invention, there are provided
the aforementioned compound, wherein Ar
1, Ar
2, Ar
3 and Ar
4 independently represent phenyl group (said phenyl group may have 1 to 5 of the same
or different substituents selected from the group consisting of hydroxyl group, alkyl
group, alkoxyl group, amino group, alkyl amino group, nitro group, cyano group, aryl
group, halogen atom); and the aforementioned compound, wherein Ar
1, Ar
2, Ar
3 and Ar
4 independently represent a 3,5-dialkyl-4-alkoxyphenyl group; and the aforementioned
compound, wherein Ar
1, Ar
2, Ar
3 and Ar
4 independently represent 3,5-dimethyl-4-methoxyphenyl group.
[0010] According to more preferred embodiments, there are provided the aforementioned compound,
wherein R
1 is hydrogen atom, and R
2 is a hydroxyalkyl group, preferably hydroxymethyl group; the aforementioned compound,
wherein R
1 is hydrogen atom, or a linear, branched or cyclic alkyl group, preferably hydrogen
atom, or methyl group, and R
2 is a triphenylmethyloxyalkyl group, preferably triphenylmethyloxymethyl group; the
aforementioned compound, wherein R
1 and R
2 combine together to represent - C(R
3)(R
4)- (R
3 and R
4 both represent hydrogen atom, or R
3 and R
4 combine together to represent oxo group); and the aforementioned compound, wherein
R
1 and R
2 combine together to represent - C(R
5)(R
6)-O-C(R
7)(R
8)- (R
5 and R
6 independently represent a linear, branched or cyclic alkyl group, preferably both
represent methyl group, and both R
7 and R
8 are hydrogen atoms).
[0011] From other aspects, there are provided a transition metal complex consisting of a
compound represented by the aforementioned general formula (I) and a transition metal,
preferably a transition metal selected from the group consisting of rhodium, ruthenium,
iridium, and palladium, and an asymmetric catalyst comprising the transition metal
complex. This asymmetric catalyst can be used as a catalyst for a catalytic asymmetric
hydrogenation reaction of double bonds in olefins, imines, ketones, or the like, and
an asymmetric 1,4-addition reaction of enones.
[0012] From further aspects, the present invention also provides a phosphine borane compound
consisting of a compound represented by the aforementioned general formula (I) having
boranes added on each of the two phosphorus atoms of the compound of the general formula
(I), and a method for preparing a compound represented by the aforementioned general
formula (I), which comprises the step of treating the phosphine borane compound with
a base.
Effect of the Invention
[0013] The compound represented by the general formula (I) provided by the present invention
is useful as an optically active phosphine ligand which can be conveniently synthesized
and provides a transition metal complex superior in asymmetric catalyst activity.
The transition metal complex comprising this optically active phosphine ligand and
a transition metal is useful as a catalyst of a catalytic asymmetric hydrogenation
reaction of a double bond. The catalyst is extremely useful especially as an asymmetric
reduction catalyst for preparation of N-protected amino acids or alkyl succinates
by an asymmetric hydrogenation reaction.
Best Mode for Carrying out the Invention
[0014] As the alkyl group, for example, a linear, branched or cyclic alkyl group or alkyl
group consisting of a combination thereof having 1 to 20, preferably 1 to 12, more
preferably 1 to 6 carbon atoms may be used. More specifically, examples include, for
example, methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group,
cyclohexyl group, and the like, but not limited to these examples. The same shall
apply to alkyl moieties in other substituents having the alkyl moiety (hydroxyalkyl
group, alkoxyl group, and the like).
[0015] As the aryl group, a monocyclic or polycyclic aromatic hydrocarbon can be used, and
examples include, for example, phenyl group, naphthyl group, and the like. The same
shall apply to aryl moieties in other substituents having the aryl moiety (e.g., triarylmethyloxyalkyl
group and the like). The aryl group or the aforementioned aryl moiety may be substituted.
The aforementioned alkyl group, alkyl moiety, aryl group, and aryl moiety may be substituted.
The number, and substitution position of the substituents are not particularly limited,
and the substituents are a hydroxyl group, an alkyl group, an alkoxyl group, amino
group, an alkylamino group, nitro group, cyano group, an aryl group, or a halogen
atom.
[0016] R
1 represents hydrogen atom, or an alkyl group. As R
1, hydrogen atom, or an alkyl group having 1 to 6 carbon atoms is preferred, hydrogen
atom, or an alkyl group having 1 to 3 carbon atoms is more preferred, and hydrogen
atom or methyl group is still more preferred.
[0017] R
2 represents a hydroxyalkyl group, or a triarylmethyloxyalkyl group. Although number
of the hydroxyl group existing in the hydroxyalkyl group represented by R
2 is not particularly limited, it is preferably, for example, 1 or 2, particularly
preferably 1. As the hydroxyalkyl group represented by R
2, a monohydroxyalkyl group having 1 to 6 carbon atoms is preferred, a monohydroxyalkyl
group having 1 to 3 carbon atoms is more preferred, and hydroxymethyl group is particularly
preferred. As the triarylmethyloxyalkyl group represented by R
2, an alkyl group having 1 to 6 carbon atoms substituted with triphenylmethyloxy group
is preferred, an alkyl group having 1 to 3 carbon atoms substituted with triphenylmethyloxy
group is more preferred, and triphenylmethyloxymethyl group is particularly preferred.
[0018] R
1 and R
2 may combine together to form a group represented by -C(R
3)(R
4)- or -C(R
6)(R
6)-O-C(R
7)(R
8)- (the left end of the group represented by -C(R
5)(R
6)-O-C(R
7)(R
8)-directly bonds to the oxygen atom to which R
1 binds). In this case, a 5-member ring and 7-member ring each containing one ring-constituting
oxygen atom are formed. R
3 and R
4 independently represent hydrogen atom, an alkyl group, or hydroxyl group, or R
3 and R
4 may combine together to represent oxo group. As the alkyl group represented by R
3 or R
4, an alkyl group having 1 to 6 carbon atoms is preferred, an alkyl group having 1
to 3 carbon atoms is more preferred, and methyl group is still more preferred. It
is preferred that both R
3 and R
4 are hydrogen atoms. It is also preferred that R
3 and R
4 combine together to represent oxo group.
[0019] R
5, R
6, R
7, and R
8 independently represent hydrogen atom, an alkyl group, or hydroxyl group. R
5 and R
6 may combine together to represent oxo group, and/or R
7 and R
8 may combine together to represent oxo group. As the alkyl group represented by R
5, R
6, R
7, or R
8, an alkyl group having 1 to 6 carbon atoms is preferred, an alkyl group having 1
to 3 carbon atoms is more preferred, and methyl group is still more preferred. It
is preferred that R
5 and R
6 are the same or different alkyl groups having 1 to 6 carbon atoms, it is more preferred
that R
5 and R
6 are the same or different alkyl groups having 1 to 3 carbon atoms, and it is still
more preferred that R
5 and R
6 are methyl groups. When R
5 and R
6 are the same or different alkyl groups, it is preferred that R
7 and R
8 are hydrogen atoms. It is particularly preferred that R
5 and R
6 are the same or different alkyl groups having 1 to 6 carbon atoms, preferably alkyl
groups having 1 to 3 carbon atoms, still more preferably methyl groups, and R
7 and R
8 are hydrogen atoms.
[0020] In the aforementioned general formula (I), it is particularly preferred that R
1 is hydrogen atom, and R
2 is a hydroxyalkyl group, preferably hydroxymethyl group; R
1 is hydrogen atom, or an alkyl group, preferably hydrogen atom, or methyl group, and
R
2 is a triphenylmethyloxyalkyl group, preferably triphenylmethyloxymethyl group; R
1 and R
2 combine together to represent -C(R
3)(R
4)- (R
3 and R
4 are hydrogen atoms, or R
3 and R
4 combine together to represent oxo group); or R
1 and R
2 combine together to represent -C(R
5)(R
6)-O-C(R
7)(R
8)- (R
5 and R
6 independently represent an alkyl group, preferably both represent methyl group, and
R
7 and R
8 are hydrogen atoms).
[0021] Ar
1, Ar
2, Ar
3, and Ar
4 independently represent an aryl group, preferably a phenyl group. The aryl group
represented by Ar
1, Ar
2, Ar
3, or Ar
4 may have 1 to 5 of the same or different substituents. As the substituent, an alkyl
group and an alkoxyl group are preferred, but not limited to these examples. It is
preferred that, for example, the aryl group represented by Ar
1, Ar
2, Ar
3, or Ar
4, preferably phenyl group, has 1 to 3 of alkyl groups having 1 to 6 carbon atoms,
preferably alkyl groups having 1 to 3 carbon atoms, more preferably methyl groups,
and 1 alkoxyl group having 1 to 6 carbon atoms, preferably alkoxyl group having 1
to 3 carbon atoms, more preferably methoxy group. As the aryl group represented by
Ar
1, Ar
2, Ar
3, or Ar
4, for example, phenyl group, 3,5-dimethyl-4-methoxyphenyl group and the like are particularly
preferred.
[0022] In the compound represented by the aforementioned general formula (I), *1, *2, *3
and *4 indicate asymmetric carbons, and relative steric configurations of the asymmetric
carbons are in cis-configuration between *1 and *2, cis-configuration between *3 and
*4, and trans-configuration between *2 and *3. The compound represented by the aforementioned
general formula (I) is preferably provided as an optically active compound.
[0023] Examples of the compound represented by the aforementioned general formula (I) are
mentioned below. However, the compound of the present invention is not limited to
these examples. In the formulas, Ph represents phenyl group, Me represents methyl
group, and Ar represents 3,5-dimethyl-4-methoxyphenyl group.

[0024] According to the present invention, a phosphine borane compound consisting of a compound
represented by the aforementioned general formula (I) having boranes added on each
of the two phosphorus atoms of the compound is provided. This borane compound is useful
as an intermediate for the preparation of the compound represented by the general
formula (I). More specifically, the following compounds are provided as the borane
compounds corresponding to the preferred examples of the compound represented by the
general formula (I) mentioned above. However, the borane compound is not limited to
the following specific compounds.

[0025] Although the method for preparing the compound represented by the aforementioned
general formula (I) is not particularly limited, the compounds mentioned above as
preferred compounds can be prepared by, for example, the methods shown below. The
details of these methods are explained in the examples, and accordingly, those skilled
in the art can easily understand that arbitrary compounds falling within the scope
of the compound represented by the general formula (I) can be prepared by referring
to the following general explanations and examples. In the following schemes, Ts represents
para-toluenesulfonyl group, Ph represents phenyl group, Me represents methyl group,
Et represents ethyl group, n-Bu represents n-butyl group, DABCO represents 1,4-diazobicyclo[2,2,2]octane,
THF represents tetrahydrofuran, DMF represents dimethylformamide, and regents and
solvents mentioned in the reaction steps are typical examples.

[0026] Compound (1) mentioned above as a starting material is called as "Corey lactone"
and widely used as an intermediate in the synthesis of naturally-occurring type prostaglandins,
and can be prepared by, for example, the method described in
J. Am. Chem. Soc., 91(20), pp.5675-5677, 1969.
[0027] For the sulfonic acid esterification (for example, conversion of Compound (1) into
Compound (2) mentioned above), sulfonic acid halides, sulfonic acid anhydrides, and
the like can be used. Examples include, for example, methanesulfonyl chloride, ethanesulfonyl
chloride, trichloromethanesulfonyl chloride, benzenesulfonyl chloride, 2-nitrobenzenesulfonyl
chloride, camphorsulfonyl chloride, trifluoromethanesulfonic anhydride, methanesulfonic
anhydride, p-toluenesulfonic anhydride, and the like. The sulfonic acid esterification
can be performed by a treatment with a sulfonic acid esterification agent in the presence
of a basic compound. As the basic compound are, for example, inorganic basic compounds
such as sodium carbonate and potassium carbonate, triethylamine, diisopropylethylamine,
pyridine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane, and the
like may be used.
[0028] Examples of the solvent used for the sulfonic acid esterification include, for example,
saturated hydrocarbons such as hexane, heptane, cyclohexane and methylcyclohexane,
aromatic solvents such as benzene, toluene, anisole and chlorobenzene, ethers such
as tetrahydrofuran, diethyl ether and cyclopentyl methyl ether, halogen type solvents
such as chloroform, dichloromethane and carbon tetrachloride, and amides such as N,N-dimethylformamide,
N,N-diethylacetamide and hexamethylphosphoric triamide, as well as solvents consisting
a mixture of these at an arbitrary ratio, if needed, but the solvents are not limited
to these examples. The volume of the solvent is 0.1 to 1000 times, preferably 1 to
100 times, based on the volume of the substrate compound. The reaction temperature
is usually -20 to 100°C. Although the reaction time may vary depending on the solvent,
temperature, concentration and the like, it is determined on the basis of the time
required to consume the reaction substrate, and is usually from 30 minutes to 24 hours.
[0029] The phosphination (for example, conversion of Compound (2) into Compound (3) mentioned
above) can be performed by, for example, reacting an anion of diphenylphosphine borane.
The anion of diphenylphosphine borane can be obtained by reacting diphenylphosphine
borane with an arbitrary anionizing agent such as alkali metals and alkali metal compounds.
Examples of the anionizing agent include, for example, simple substances of alkali
metals such as metal sodium and metal potassium, solutions of methyllithium, phenyllithium,
n-butyllithium, sec-butyllithium, and tert-butyllithium, dispersion of sodium hydride,
potassium tert-butoxide, and the like. Examples of the solvent include, for example,
saturated hydrocarbons such as heptane, hexane, cyclohexane and methylcyclohexane,
aromatic solvents such as benzene, toluene and anisole, ethers such as tetrahydrofuran,
diethyl ether and cyclopentyl methyl ether, halogen type solvents such as chloroform,
dichloromethane and carbon tetrachloride, amides such as N,N-dimethylformamide, N,N-diethylacetamide
and hexamethylphosphoric triamide, or if needed, a solvent as a mixture thereof at
an arbitrary ratio, however the solvents are not limited to these examples. The volume
of the solvent is 0.1 to 1000 times, preferably 1 to 100 times, based on the volume
of the substrate. The reaction temperature is usually -100 to 100°C. Although the
reaction time may vary depending on the solvent, temperature, concentration and the
like, the time is determined on the basis of the time required to consume the reaction
substrate, and is usually from 1 to 24 hours.
[0030] The deboranation reaction (for example, conversion of Compound (3) into CLPL-S mentioned
above) can be performed by allowing a base compound such as amine to react on the
borane compound obtained by the phosphination. As the base compound, for example,
various organic amines can be used, and more specifically, examples include, for example,
diethylamine, morpholine, pyrrolidine, piperidine, triethylamine, 1,8-diazabicyclo[5.4.0]-7-undecene,
1,4-diazabicyclo[2.2.2]octane, and the like. Although the deboranation reaction may
be performed without solvent, a solvent may be used. Examples of the solvent include,
for example, saturated hydrocarbons such as heptane, hexane, cyclohexane and methylcyclohexane,
aromatic solvents such as benzene, toluene, anisole and chlorobenzene, ethers such
as tetrahydrofuran, diethyl ether and cyclopentyl methyl ether, and amides such as
N,N-dimethylformamide, N,N-diethylacetamide and hexamethylphosphoric triamide, or
if needed, a solvent as a mixture thereof at an arbitrary ratio. The volume of the
solvent is 0.1 to 1000 times, preferably 1 to 100 times, based on the volume of the
substrate. The reaction temperature is usually -20 to 150°C. Although the reaction
time may vary depending on the solvent, temperature, concentration and the like, the
time is determined on the basis of the time required to consume the reaction substrate,
and is usually from 10 minutes to 24 hours.
[0031] The ring opening of the lactone ring (for example, conversion of Compound (3) into
Compound (4) mentioned above) can be performed by reduction using a hydride compound.
Examples of the hydride compound include, for example, lithium aluminum hydride, lithium
borohydride, sodium borohydride, sodium bismethoxyethoxydihydroaluminate toluene solution,
and the like. Although the solvent used in the reduction reaction is not particularly
limited, examples of the solvent include, for example, saturated hydrocarbons such
as heptane, hexane, cyclohexane and methylcyclohexane, aromatic solvents such as benzene,
toluene, anisole and chlorobenzene, and ethers such as tetrahydrofuran, diethyl ether
and cyclopentyl methyl ether, or if needed, a solvent as a mixture thereof at an arbitrary
ratio. The volume of the solvent is 0.1 to 1000 times, preferably 1 to 100 times,
based on the volume of the substrate. The reaction temperature is usually -100 to
100°C. Although the reaction time may vary depending on the solvent, temperature,
concentration and the like, the time is determined on the basis of the time required
to consume the reaction substrate, and is usually from 1 to 24 hours.
[0032] The etherification (for example, conversion of Compound (6) into Compound (7) mentioned
above) can be performed by various generally known etherification methods. Examples
include, for example, methods utilizing an alkylating agent such as alkyl halides,
sulfuric acid alkyl esters and sulfonic acid alkyl esters, an aralkylating agent such
as aralkyl halides, sulfuric acid aralkyl esters and sulfonic acid aralkyl esters,
or an arylating agent such as aryl halides, and a basic compound, but the methods
are not limited to these examples. Examples of the alkylating agent such as alkyl
halides, sulfuric acid alkyl esters and sulfonic acid alkyl esters include, for example,
iodomethane, ethyl bromide, isopropyl bromide, dimethyl sulfate, diethyl sulfate,
methyl p-toluenesulfonate, methyl trifluoromethanesulfonate, and the like. Examples
of the aralkyl halides, sulfuric acid aralkyl esters and sulfonic acid aralkyl esters
include, for example, benzyl bromide, triphenylmethane chloride, dibenzyl sulfate,
benzyl methanesulfonate, and the like. Examples of the arylating agent such as aryl
halides include, for example, iodobenzene, bromotoluene, iodonaphthalene, and the
like. As the basic compound, for example, alkali metal compounds, organic bases, and
the like can be used. Examples include, for example, sodium hydroxide, potassium hydroxide,
sodium carbonate, potassium carbonate, cesium carbonate, sodium hydride, potassium
tert-butoxide, triethylamine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane,
and the like, but the basic compounds are not limited to these examples. In the case
of the arylation, a transition metal compound such as copper(1) iodide and copper(1)
bromide can also be used as the catalyst as well as the aforementioned basic compounds.
[0033] Examples of the solvent used for the etherification include, for example, saturated
hydrocarbons such as heptane, hexane, cyclohexane and methylcyclohexane, aromatic
solvents such as benzene, toluene, anisole and chlorobenzene, ethers such as tetrahydrofuran,
diethyl ether and cyclopentyl methyl ether, halogen type solvents such as chloroform,
dichloromethane and carbon tetrachloride, and amides such as N,N-dimethylformamide,
N,N-diethylacetamide and hexamethylphosphoric triamide, or if needed, a solvent as
a mixture thereof at an arbitrary ratio. The volume of the solvent is 0.1 to 1000
times, preferably 1 to 100 times, based on the volume of the substrate compound. The
reaction temperature is usually -20 to 150°C. Although the reaction time may vary
depending on the solvent, temperature, concentration and the like, the time is determined
on the basis of the time required to consume the reaction substrate, and is usually
from 30 minutes to 24 hours.
[0034] The oxepane cyclization reaction (for example, conversion of Compound (4) into Compound
(8) mentioned above) can be performed by reacting a diol compound with a ketone, an
aldehyde, or a derivative thereof under an acidic condition. Examples of the ketone
or ketone derivative include, for example, acetone, 2-butanone, 3-pentanone, cyclohexanone,
2,2-dimethoxypropane, 2,2-diethoxypropane, 2,2-dimethyl-1,3-oxolane, and the like.
Examples of the aldehyde or aldehyde derivative include, for example, formaldehyde,
isopropylaldehyde, benzaldehyde, 1,1-dimethoxyethane, 1,1-dimethoxy-2-methylethane,
and the like. The acid is not particularly limited, and examples include hydrochloric
acid, sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, strongly acidic
ion exchange resins, and the like. Although reactants may serve as a solvent, the
reaction may be performed by using a solvent. For example, solvents such as saturated
hydrocarbons such as heptane, hexane, cyclohexane and methylcyclohexane, aromatic
solvents such as benzene, toluene, anisole and chlorobenzene, ethers such as tetrahydrofuran,
diethyl ether and cyclopentyl methyl ether, halogen type solvents such as chloroform,
dichloromethane and carbon tetrachloride, and amides such as N,N-dimethylformamide,
N,N-diethylacetamide and hexamethylphosphoric triamide, or if needed, a solvent as
a mixture thereof at an arbitrary ratio may be used. The volume of the solvent is
0.1 to 1000 times, preferably 1 to 100 times, based on the volume of the substrate.
The reaction temperature is usually -20 to 150°C.
[0035] The cyclization reaction of the diol compound using a sulfonic acid compound (for
example, conversion of Compound (4) into Compound (5) mentioned above) can be performed
in the presence of a basic compound. As the sulfonic acid compound, sulfonic acid
halides, sulfonic acid anhydrides, and the like can be used. Examples include, for
example, methanesulfonyl chloride, ethanesulfonyl chloride, trichloromethanesulfonyl
chloride, p-toluenesulfonyl chloride, benzenesulfonyl chloride, 2-nitrobenzenesulfonyl
chloride, camphorsulfonyl chloride, trifluoromethanesulfonic anhydride, methanesulfonic
anhydride, p-toluenesulfonic anhydride, and the like. Examples of the basic compound
include, for example, inorganic basic compounds such as sodium carbonate and potassium
carbonate, triethylamine, diisopropylethylamine, pyridine, 1,8-diazabicyclo[5.4.0]-7-undecene,
1,4-diazabicyclo[2.2.2]octane, and the like. Examples of the solvent include, for
example, saturated hydrocarbons such as hexane, heptane, cyclohexane and methylcyclohexane,
aromatic solvents such as benzene, toluene, anisole and chlorobenzene, ethers such
as tetrahydrofuran, diethyl ether and cyclopentyl methyl ether, halogen type solvents
such as chloroform, dichloromethane and carbon tetrachloride, and amides such as N,N-dimethylformamide,
N,N-diethylacetamide and hexamethylphosphoric triamide, or if needed, a solvent as
a mixture thereof at an arbitrary ratio. The volume of the solvent is 0.1 to 1000
times, preferably 1 to 100 times, based on the volume of the substrate. The reaction
temperature is usually -20 to 100°C. Although the reaction time may vary depending
on the solvent, temperature, concentration and the like, the time is determined on
the basis of the time required to consume the reaction substrate, and is usually from
30 minutes to 24 hours.
[0036] The compound represented by the aforementioned general formula (I) provided by the
present invention is useful as a ligand of a transition metal complex. As the transition
metal contained in the transition metal complex provided by the present invention,
the transition metals of the 4th and 5th periods, preferably rhodium (Rh), ruthenium
(Ru), iridium (Ir), and palladium (Pd), can be used. The aforementioned transition
metal complex can be obtained by reacting or mixing a transition metal with the compound
represented by the aforementioned general formula (I). The aforementioned complex
is a complex compound of a transition metal atom and the molecule of the compound
represented by the aforementioned general formula (I) in a ratio of 1:1 to 1:5, preferably
1:1. This transition metal complex can be used as a catalyst for a catalytic asymmetric
hydrogenation reaction as explained below, and for use as a catalyst, the complex
may be an isolated complex, or in the form of a solution or slurry after preparation
of the transition metal complex in a reaction system.
[0037] When rhodium is used as the transition metal, for the preparation and isolation of
the complex, the method described in "
Organic Metal Complex", Jikken Kagaku Koza (Lecture of Experimental Chemistry), 4th
edition, edited by the Chemical Society of Japan, vol. 18, pp.339-344, 1991, Maruzen can be referred to. For the preparation of the rhodium complex, for example,
the following rhodium compounds can be used (in the formulas, L represents the compound
represented by the general formula (I), cod represents 1,5-cyclooctadiene, and nbd
represents norbornadiene): [Rh(cod)(L)]BF
4, [Rh(cod)(L)]ClO
4, [Rh(cod)(L)]PF
6, [Rh(cod)(L)]OSO
2CF
3, [Rh(nbd)(L)]BF
4, [Rh(nbd)(L)]ClO
4, [Rh(nbd)(L)]PF
6, [Rh(nbd)(L)]OSO
2CF
3. Further, when the rhodium complex is used without isolation, a rhodium compound
and the compound represented by the general formula (I) can be dissolved and reacted
in an appropriate solvent, and the reaction mixture without any treatment or the reaction
mixture concentrated by an appropriate means can be used. Examples of the rhodium
compound usable in such a case include, for example, the following compounds (in the
formulas, cod and nbd have the same meanings as those mentioned above, and acac represents
acetylacetonato): [Rh(cod)
2]BF
4, [Rh(cod)
2]ClO
4, [Rh(cod)
2]PF
6, [Rh(cod)
2]OSO
2CF
3, [Rh(nbd)
2]BF
4, [Rh(nbd)
2]ClO
4, [Rh(nbd)
2]PF
6, [Rh(nbd)
2]OSO
2CF
3, [RhCl(cod)]
2, [RhCl(nbd)]
2, [Rh(acac)(cod)].
[0038] Examples of the solvent include, for example, alcohols such as methanol, ethanol,
2-propanol, 2-methyl-2-propanol and cyclohexanol, saturated hydrocarbons such as heptane,
hexane, cyclohexane and methylcyclohexane, aromatic solvents such as benzene, toluene,
anisole and chlorobenzene, ethers such as tetrahydrofuran, diethyl ether and cyclopentyl
methyl ether, halogen type solvents such as chloroform, dichloromethane and carbon
tetrachloride, and amides such as N,N-dimethylformamide, N,N-diethylacetamide and
hexamethylphosphoric triamide, or if needed, a solvent as a mixture thereof at an
arbitrary ratio, however, the solvents are not limited to these examples.
[0039] When ruthenium is used as the transition metal, for the preparation and isolation
of the complex, the method described in
M. Kitamura, Org. Synth., 71, pp.1-13 can be referred to, and as described in the publication, a method of heating the
compound represented by the general formula (I) with [Ru(cod)Cl
2]n in dimethylformamide (DMF), or the like can be employed.
[0041] When iridium is used as the transition metal, for the preparation and isolation of
the complex, the method described in "
Organic Metal Complex", Jikken Kagaku Koza (Lecture of Experimental Chemistry), 4th
edition, edited by the Chemical Society of Japan, vol. 18, p.363, 1991, Maruzen can be referred to. For the preparation of the iridium complex, for example, the
following rhodium compounds can be used (L, cod and nbd have the same meanings as
those mentioned above): [Ir(cod)(L)]BF
4, [Ir(cod)(L)]ClO
4, [Ir(cod)(L)]PF
6, [Ir(cod)(L)]OSO
2CF
3, [Ir(nbd)(L)]BF
4, [Ir(nbd)(L)]ClO
4, [Ir(nbd)(L)]PF
6, [Ir(nbd)(L)]OSO
2CF
3. Further, when the iridium complex is used without isolation, an iridium compound
and the compound represented by the general formula (I) can be dissolved and reacted
in an appropriate solvent, and the reaction mixture can be used without any treatment
or the reaction mixture concentrated by an appropriate means can be used. Examples
of the iridium compound used in the above case include, for example, the following
compounds (in the formulas, cod, nbd and acac have the same meanings as those mentioned
above): [Ir(cod)
2]BF
4, [Ir(cod)
2]ClO
4, [Ir(cod)
2]PF
6, [Ir(cod)
2]OSO
2CF
3, [Ir(nbd)
2]BF
4, [Ir(nbd)
2]ClO
4, [Ir(nbd)
2]PF
6, [Ir(nbd)
2]OSO
2CF
3, [IrCl(cod)]
2, [IrCl(nbd)]
2, [Ir(acac)(cod)]. As the solvent, the same solvents as those mentioned above for
the case of rhodium can be used.
[0042] The aforementioned transition metal complex consisting of a transition metal atom
and the compound represented by the aforementioned general formula (I) as a ligand
is useful as, for example, a catalyst of a catalytic asymmetric hydrogenation reaction.
Examples of a chemical bond which can be reduced by the catalytic asymmetric hydrogenation
reaction include, for example, carbon-carbon double bond, carbon-carbon triple bond,
carbon-nitrogen double bond, carbon-oxygen double bond, and the like. Among them,
preferred reactions include reductions of an olefin (C=C), an imine (C=N), and a ketone
(C=O). By performing a catalytic asymmetric hydrogenation reaction using the asymmetric
catalyst containing the transition metal complex of the present invention, an unsaturated
bond can be stereoselectively reduced, and thus an optical isomer with a high optical
purity can be easily prepared. For example, by carrying out asymmetric hydrogenation
of an alkylidene succinate derivative using the catalyst of the present invention,
an alkyl succinate derivative with a high optical purity can be easily prepared. Further,
by carrying out asymmetric hydrogenation of an N-protected aminoacrylate derivative
using the catalyst of the present invention, a protected amino acid derivative with
a high optical purity can be easily prepared.
[0043] A molar ratio of a substrate containing an unsaturated bond and the complex as a
catalyst (S/C) is, for example, about 100 to 100,000. The catalytic asymmetric hydrogenation
can be performed at a reaction temperature of, for example, about -20 to 200°C, preferably
0 to 80°C. Hydrogen pressure may be, for example, about 0.01 to 25 MPa, preferably
0.1 to 10 MPa. The reaction solvent can be suitably chosen from viewpoints of stability,
reactivity and the like of the substrate. For example, alcohols such as methanol,
ethanol, 2-propanol, 2-methyl-2-propanol and cyclohexanol, saturated hydrocarbons
such as heptane, hexane, cyclohexane and methylcyclohexane, aromatic solvents such
as benzene, toluene, anisole and chlorobenzene, ethers such as tetrahydrofuran, diethyl
ether and cyclopentyl methyl ether, halogen type solvents such as chloroform, dichloromethane
and carbon tetrachloride, and amides such as N,N-dimethylformamide, N,N-diethylacetamide
and hexamethylphosphoric triamide, or if needed, a solvent as a mixture thereof at
an arbitrary ratio may be used.
Examples
[0045] The present invention will be more specifically explained with reference to examples.
However, the scope of the present invention is not limited by the following examples.
In the following examples, the abbreviations of the compounds (CLPL-S and the like)
and the numbers of the compounds are the same as those used for the preferred compounds
mentioned above.
Example 1: Preparation of (3aR,4S,5R,6aS)-5-p-toluenesulfoxy-4-[(p-toluenesulfoxy)methyl]hexahydrocyclopenta[b]furan-2-one
(Compound 2)
[0046] To a 200 ml-three-neck flask attached with a dropping funnel were added p-toluenesulfonyl
chloride (37.0 g, 190 mmol), and 60 mL of pyridine, and the mixture was cooled on
an ice bath. The mixture was added dropwise with a solution of (3aR,4S,5R,6aS)-5-hydroxy-4-hydroxymethylhexahydrocyclopenta[b]furan-2-one
(Compound 1, 8.6 g, 50 mmol) in 40 mL of pyridine, stirred for 30 minutes, then warmed
to room temperature, and further stirred for 2.5 hours. The mixture was again cooled
on an ice bath, and slowly added with 50 mL of ice water. The mixture was stirred
at room temperature for 10 minutes, and then added with 80 mL of ethyl acetate, the
layers were separated, and further the aqueous layer was extracted twice with 30 mL
of ethyl acetate. The organic layers were combined, and washed five times with 50
mL of diluted hydrochloric acid and once with 40 mL of saturated brine in this order.
The organic layer was dried over anhydrous magnesium sulfate, and after the drying
agent was removed by filtration, concentrated in an evaporator. The residue was added
with 150 mL of methanol, and the mixture was stirred at 70°C for 30 minutes with heating,
and then crystallized at 5 to 10°C by cooling. The precipitated solid was collected
by filtration, and dried in a desiccator to obtain (3aR,4S,5R,6aS)-5-p-toluenesulfoxy-4-[(p-toluenesulfoxy)methyl]hexahydrocyclopenta-[b]furan-2-one
(Compound 2) as white crystals (17.5 g, yield: 73%).
1H NMR (CDCl
3, 300MHz): δ 7.77-7.72 (m, 4H), 7.40-7.33 (m, 4H), 4.87-4.76 (m, 2H), 4.04-3.94 (m,
2H), 2.81-2.73 (m, 2H), 2.48 (s, 3H), 2.46 (s, 3H), 2.44-2.26 (m, 3H), 2.26-2.04 (m,
1H)
m.p.: 41 to 43°C
[α]D
20 = -57.70 (c=1.02, toluene)
Example 2: Preparation of (3aR,4S,5S,6aS)-(5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one-borane
complex (Compound 3)
[0047] To a 200 mL-three-neck flask attached with a dropping funnel and a three-way cock
were added diphenylphosphine-borane complex (7.9 g, 39.5 mmol) and 45 mL of dehydrated
THF, and the mixture was cooled to -15°C, and slowly added dropwise with a 1.56 mol/L
solution of n-butyllithium (25.3 mL, 39.5 mmol) in hexane. The mixture was stirred
for 10 minutes, then added dropwise with a solution of (3aR,4S,5R,6aS)-5-p-toluenesulfoxy-4-[(p-toluenesulfoxy)methyl]hexahydrocyclopenta[b]furan-2-one
(Compound 2, 7.3 g, 15.2 mmol) in 20 mL of tetrahydrofuran, and stirred at room temperature
for 16 hours. The reaction mixture was added with 40 mL of diethyl ether and 20 mL
of saturated brine, the layers were separated, and the aqueous layer was extracted
twice with 20 mL of diethyl ether. The organic layers were combined, and washed twice
with 10 mL of saturated brine. The organic layer was dried over anhydrous magnesium
sulfate, and after the drying agent was removed by filtration, concentrated in an
evaporator. The residue was purified by silica gel column chromatography (toluene:ethyl
acetate = 10:1) to obtain (3aR,4S,5S,6aS)-(5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one-borane
complex (Compound 3, 4.41 g, yield: 54%).
1H NMR (CDCl
3, 300MHz): δ 7.79-7.13 (m, 20H), 5.04-5.00 (t, J=5.1Hz, 1H), 3.28-3.11 (m, 2H), 2.90-2.77
(m, 2H), 2.56-2.38 (m, 1H), 2.35-2.02 (m, 4H), 1.08 (brs, 6H)
[α]
D20 = -40.94 (c=1.00, toluene)
Example 3: Preparation of (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-hydroxyethyl)cyclopentanol-borane
complex (Compound 4)
[0048] To a 50 mL-three-neck flask attached with a thermometer and a three-way cock were
added lithium borohydride (0.20 g, 9.3 mmol) and 10 mL of dehydrated tetrahydrofuran,
and the mixture was cooled on an ice bath. The mixture was added dropwise with a solution
of (3aR,4S,5S,6aS)-5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one-borane
complex (Compound 3, 2.5 g, 4.7 mmol) in 15 mL of dehydrated tetrahydrofuran, and
stirred at room temperature for 16 hours. The reaction mixture was cooled, added with
15 mL of toluene and 10 mL of diluted hydrochloric acid, and the mixture was stirred
for 15 minutes. The layers were separated, the aqueous layer was extracted three times
with 5 mL of toluene, and the organic layers were combined, and washed three times
with 5 mL of saturated brine. The organic layer was dried over anhydrous magnesium
sulfate, and after the drying agent was removed by filtration, concentrated in an
evaporator. The residue was purified by silica gel column chromatography (toluene:ethyl
acetate = 1:1) to obtain (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-hydroxyethyl)cyclopentanol-borane
complex (Compound 4, 2.2 g, yield: 86%).
1H NMR (CDCl
3, 300MHz): δ 7.89-7.11 (m, 20H), 4.27 (s, 1H), 3.59-3.46 (m, 2H), 3.2-3.22 (m, 1H),
2.64 (t, J=13.8Hz, 1H), 2.41-2.26 (m, 3H), 2.05 (brs, 1H), 1.81 (m, 1H), 1.68-1.57
(m, 1H), 1.45-1.41 (m, 1H), 1.03 (brs, 6H)
[α]
D20 = +17.94 (c = 1.01, toluene)
Example 4: Preparation of (3aS,4R,5R,6aR)-5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan-borane
complex (Compound 5)
[0049] To a 25 mL three-neck flask attached with a three-way cock were added pyridine (0.17
mL, 2.06 mmol) and 4 mL of dichloromethane, and the reaction mixture was cooled. To
the flask were added p-toluenesulfonic acid anhydride (336 mg, 1.03 mmol) and a solution
of (3aS,4R,5R,6aR)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-hydroxyethyl)cyclopentanol-borane
complex (enantiomer of Compound 4) in 2 mL of dichloromethane, and the mixture was
stirred for 4 hours. The reaction mixture was stirred at room temperature for 14 hours,
then cooled, and added with 5 mL of water, and the mixture was stirred for 30 minutes.
The reaction mixture was transferred to a separatory funnel, and extracted three times
with 5 mL of toluene. The organic layers were combined, and washed five times with
5 mL of diluted hydrochloric acid and then with 5 mL of saturated brine. The organic
layer was dried over anhydrous magnesium sulfate, and after the drying agent was removed
by filtration, concentrated in an evaporator. The residue was purified by silica gel
column chromatography (toluene:ethyl acetate =12:1) to obtain (3aS,4R,5R,6aR)-5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]-hexahydrocyclopenta[b]furan-borane
complex (Compound 5, 140 mg, yield: 65%).
1H NMR (CDCl
3, 300MHz): δ 7.77-7.10 (m, 20H), 4.39-4.32 (m, 1H), 3.87-3.80 (m, 1H), 3.39-3.31 (m,
1H), 3.29-3.18 (m, 1H), 3.02-2.92 (m, 2H), 2.39-2.05 (m, 4H), 1.86 (dd, J=5.4, 15.0Hz,
1H), 1.50-1.37 (m, 1H), 1.20 (brs, 6H)
[α]
D20 = +32.15 (c=1.03, toluene)
Example 5: Preparation of (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-triphenylmethyloxyethyl)cyclopentanol-borane
complex (Compound 6)
[0050] To a 25 mL-recovery flask were added (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3- [(diphenylphosphanyl)methyl]2-(2-hydroxyethyl)cyclopentanol-borane
complex (Compound 4, 0.54 g, 1.0 mmol), 5 mL of dichloromethane, and triethylamine
(0.18 mL, 1.3 mmol), and the mixture was stirred with cooling for dissolution. The
solution was added dropwise with a solution of triphenylmethane chloride (0.42 g,
1.5 mol) in 2 mL of dichloromethane. The reaction mixture was stirred at room temperature
for 16 hours, then cooled, and added with 20 mL of toluene and 10 mL of water. The
reaction mixture was transferred to a separatory funnel to separate the layers, and
the aqueous layer was extracted three times with 5 mL of toluene. Then, the organic
layers were combined, and washed three times with 5 mL of saturated brine. The organic
layer was dried over anhydrous magnesium sulfate, and after the drying agent was removed
by filtration, concentrated in an evaporator to obtain (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-
[(diphenylphosphanyl)methyl] -2-(2-triphenylmethyloxyethyl)cyclopentanol-borane complex
(Compound 6, 0.9 g). This compound was used in the following step without purification.
1H NMR (CDCl
3, 300MHz): δ 7.89-7.06 (m, 35H), 4.18 (brs, 1H), 3.61-3.47 (m, 1H), 3.41 (brs, 1H),
3.11-3.08 (m, 1H), 2.57-2.19 (m, 4H), 1.89-1.39 (m, 4H), 0.94 (brs, 6H)
[α]
D20 = -4.96 (c=0.99, toluene)
Example 6: Preparation of (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-triphenylmethyloxyethyl)-1-methoxycyclopentane-borane
complex (Compound 7)
[0051] To a 25 mL-recovery flask were added sodium hydride (30.9 mg, 0.77 mmol) and 2 mL
of dimethylformamide, and the mixture was cooled on an ice bath. The mixture was added
dropwise with a solution of (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-triphenylmethyloxyethyl)cyclopentanol-borane
complex (Compound 6, 0.52 g, 0.55 mmol) in 4 mL of dimethylformamide, and the mixture
was stirred at room temperature for 30 minutes, and then added dropwise with methyl
iodide (0.17 mL, 1.3 mmol). The mixture was stirred overnight, then cooled, and added
with 10 mL of toluene and 3 mL of water. The reaction mixture was transferred to a
separatory funnel to separate the layers, the aqueous layer was extracted twice with
3 mL of toluene, and the organic layers were combined and washed twice with 5 mL of
saturated brine. The organic layer was dried over anhydrous magnesium sulfate, and
after the drying agent was removed by filtration, concentrated in an evaporator. The
residue was purified by silica gel column chromatography (toluene) to obtain (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-trityloxyethyl)-1-methoxycyclopentane-borane
complex (Compound 7, 0.19 g, yield: 43% from (3aR,4S,5S,6aS)-3,4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-hydroxyethyl)cyclopentanol-borane
complex).
1H NMR (CDCl
3, 300MHz): δ 7.84-7.07 (m, 35H), 3.49-3.32 (m, 2H), 2.87-2.74 (m, 1H), 2.82 (s, 3H),
2.67-2.29 (m, 4H), 2.23-2.09 (m, 1H), 1.95-1.88 (m, 1H), 1.71-1.54 (m, 2H), 1.46-1.31
(m, 1H), 1.05 (brs, 6H)
[α]
D20 = +30.16 (c=1.14, toluene)
Example 7: Preparation of (5aR,6S,7S,8aS)-7-diphenylphosphanyl-6-[(diphenylphosphanyl)methyl]-2,2-dimethylhexahydrocyclopenta[d]
[1,3]dioxepine-borane complex (Compound 8)
[0052] To a 30 ml-two-neck flask were added (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-hydroxyethyl)cyclopentanol-borane
complex (Compound 4, 0.54 g, 1.0 mmol), 10 mL of 2,2-dimethoxypropane and about 10
mg of p-toluenesulfonic acid monohydrate, and the mixture was stirred at 50°C for
3 hours. The reaction mixture was cooled to room temperature, and the solvent was
concentrated in an evaporator. The residue was purified by silica gel column chromatography
(toluene) to obtain (5aR,6S,7S,8aS)-7-diphenylphosphanyl-6-[(diphenylphosphanyl)methyl]-2,2-dimethylhexahydrocyclopenta[d][1,3]dioxepine-borane
complex (Compound 8, 0.27 g, yield: 47%).
1H NMR (CDCl
3, 300MHz): δ 7.89-7.13 (m, 20H), 4.42 (t, J=6.2Hz, 1H), 3.74-3.66 (m, 1H), 3.37-3.23
(m, 2H), 2.50-2.21 (m, 5H), 1.96-1.70 (m, 2H), 1.46-1.34 (m, 1H), 1.28 (s, 3H), 1.19
(s, 3H)
[α]
D20 = -2.32 (c=1.01, toluene)
Example 8: Preparation of (3aR,4S,5S,6aS)-5-di(4-methoxy-3,5-dimethylphenyl)phosphanyl]-4-[(di(4-methoxy-3,5-dimethylphenyl)phosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one-borane
complex (Compound 9)
[0053] To a 30 mL-two-neck flask were added di(4-methoxy-3,5-dimethylphenyl)phosphine-borane
complex (0.52 g, 1.7 mmol) and 4 mL of dehydrated THF, and the mixture was cooled
to -15°C, and slowly added dropwise with a 1.54 mol/L solution of n-butyllithium (1.1
mL, 1.7 mmol) in hexane. The mixture was stirred for 10 minutes, and then added dropwise
with a solution of (3aR,4S,5R,6aS)-5-p-toluenesulfoxy-4-[(p-toluenesulfoxy)methyl]hexahydrocyclopenta[b]furan-2-one
(Compound 2, 0.33 g, 0.7 mmol) in 4 mL of tetrahydrofuran, and the mixture was stirred
at room temperature for 16 hours. The reaction mixture was added with 40 mL of diethyl
ether and 20 mL of saturated brine, the layers were separated, and the aqueous layer
was extracted twice with 20 mL of diethyl ether. The organic layers were combined,
and washed twice with 10 mL of saturated brine. The organic layer was dried over anhydrous
magnesium sulfate, and after the drying agent was removed by filtration, concentrated
in an evaporator. The residue was purified by silica gel column chromatography (toluene:ethyl
acetate = 10:1) to obtain (3aR,4S,5S,6aS)-5-di(4-methoxy-3,5-dimethylphenyl)phosphanyl]-4-[(di(4-methoxy-3,5-dimethylphenyl)phosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one-borane
complex (Compound 9, 0.10 g, yield: 19%).
1H NMR (CDCl
3, 300MHz): δ 7.37-7.23 (m, 6H), 7.00 (d, J=10.5Hz, 2H), 4.94 (t, J=5.9Hz, 1H), 3.73
(s, 3H), 3.71 (s, 3H), 3.69 (s, 3H), 3.68 (s, 3H), 3.15-3.02 (m, 1H), 2.92-2.88 (m,
1H), 2.71-2.04 (m, 7H), 2.29 (s, 6H),2.25 (s, 6H), 2.22 (s, 6H), 2.17 (s, 6H), 1.15
(brs, 6H)
[α]
D20 = -38.66 (c=1.03, toluene)
Example 9: Preparation of (3aR,4S,5S,6aS)-(5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one
(CLPL-S)
[0054] To a 25 mL-recovery flask were added (3aR,4S,5S,6aS)-(5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one-borane
complex (Compound 3, 1.0 mmol) and 1,4-diazobicyclo[2,2,2]octane (DABCO, 0.25 g, 2.2
mmol), and the atmosphere in the flask was substituted with nitrogen. The mixture
was added with 10 mL of deoxygenized toluene, and stirred at 40°C for 3 hours. The
solvent was concentrated in an evaporator, and the residue was purified by silica
gel column chromatography (toluene/ethyl acetate = 20/1 to 4/1) to obtain (3aR,4S,5S,6aS)-(5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one
(CLPL-S, yield: 85%).
1H NMR (CDCl
3, 300MHz): δ 7.45-7.01 (m, 20H), 5.07 (t, J=5.7Hz, 1H), 3.35 (brs, 1H), 3.03-2.94
(m, 1H), 2.89 (dd, J=10.6, 18.7Hz, 1H), 2.72-2.66 (m, 1H), 2.23 (dd, J=3,2, 18.8Hz,
1H), 2.15-2.01 (m, 1H), 1.97-1.79 (m, 3H)
[α]
D20 = -139.57 (c=1.01, toluene)
Example 10: Preparation of (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-hydroxyethyl)cyclopentanol
(CLPDO-S)
[0055] The target compound was obtained from (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-hydroxyethyl)cyclopentanol-borane
complex (Compound 4) in the same manner as that of Example 9 at a yield of 84%.
1H NMR (CDCl
3, 300MHz): δ 7.59-7.53 (m, 2H), 7.46-7.08 (m, 16H), 7.02-6.97 (m, 2H), 4.35 (t, J=4.8Hz,
1H), 3.80-3.74 (m, 1H), 3.67-3.60 (m, 1H), 3.33-3.23 (m, 1H), 2.69-2.63 (m, 1H), 2.30-2.21
(m, 1H), 2.05-1.76 (m, 5H), 2.00 (brs, 2H), 1.62 (dd, J=6.0, 12.0Hz, 1H)
[α]
D20 = -74.45 (c=1.00, toluene)
Example 11: Preparation of (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-triphenylmethyloxyethyl)cyclopentanol
(CLPTO-S)
[0056] The target compound was obtained from (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-triphenylmethyloxyethyl)cyclopentanol-borane
complex (Compound 6) in the same manner as that of Example 9 at a yield of 87%.
1H NMR (CDCl
3, 300MHz): δ 7.58-7.52 (m, 2H), 7.43-7.06 (m, 41H), 6.97-6.92 (m, 2H), 4.19 (brs,
1H), 3.45-3.40 (m, 1H), 3.35-3.28 (m, 2H), 3.05-3.00 (m, 1H), 2.61 (dd, J=5.3, 10.4Hz,
1H), 2.09-1.80 (m, 6H), 1.63 (dd, J=6.2, 13.1Hz, 1H)
[α]
D20 = -45.41 (c=1.02, toluene)
Example 12: Preparation of (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-triphenylmethyloxyethyl)-1-methoxycyclopentane
(CLPTM-S)
[0057] The target compound was obtained from (3aR,4S,5S,6aS)-4-diphenylphosphanyl-3-[(diphenylphosphanyl)methyl]-2-(2-trityloxyethyl)-1-methoxycyclopentane-borane
complex (Compound 7) in the same manner as that of Example 9 at a yield of 87%.
1H NMR (CDCl
3, 300MHz): δ 7.47-6.98 (m, 35H), 3.50 (brs, 1H), 3.12 (m, 2H), 2.90 (s, 3H), 2.90
(m, 1H), 2.60-2.57 (m, 1H), 2.35 (m, 1H), 1.99-1.54 (m, 6H)
[α]
D20= -16.31 (c=0.98, toluene)
Example 13: Preparation of (3aS,4R,5R,6aR)-5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan
(CLPF-R)
[0058] The target compound was obtained from (3aS,4R,5R,6aR)-5-diphenylphosphanyl-4-[(diphenylphosphanyl)methyl]hexahydrocyclopenta[b]furan-borane
complex (Compound 5) in the same manner as that of Example 9 at a yield of 100%.
1H NMR (CDCl
3, 300MHz): δ 7.47-7.06 (m, 20H), 4.45 (t, J=6.2Hz, 1H), 3.90-3.84 (m, 1H), 3.53-3.45
(m, 1H), 3.16-2.98 (m, 2H), 2.72-2.66 (m, 1H), 2.23-2.14 (m, 1H), 2.04-1.72 (m, 4H),
1.53-1.42 (m, 1H)
[α]
D20 = +117.83 (c=1.00, toluene)
Example 14: Preparation of (3aR,4S,5S,6aS)-7-diphenylphosphanyl-6-[(diphenylphosphanyl)methyl]-2,2-dimethylhexahydrocyclopenta[d][1,3]dioxepine
(CLPOX-S)
[0059] The target compound was obtained from (3aR,4S,5S,6aS)-7-diphenylphosphanyl-6- [(diphenylphosphanyl)methyl]
2,2 - dimethylhexahydrocyclopenta[d][1,3]dioxepine-borane complex (Compound 8) in
the same manner as that of Example 9 at a yield of 79%.
1H NMR (CDCI
3, 300MHz): δ 7.37-7.13 (m, 6H), 7.00 (d, J=10.5Hz, 2H), 4.94 (t, J=5.9Hz, 1H), 3.73
(s, 3H), 3.71 (s, 3H), 3.69 (s, 3H), 3.68 (s, 3H), 3.15-3.02 (m, 1H), 2.92-2.88 (m,
1H), 2.71-2.04 (m, 7H), 2.29 (s, 3H), 2.25 (s, 3H), 2.22 (s, 3H), 2.17 (s, 3H), 1.15
(brs, 6H)
[α]
D20 = -79.72 (c=1.20, toluene)
Example 15: Preparation of (3aR,4S,5S,6aS)-5-di(4-methoxy-3,5-dimethylphenyl)phosphanyl]-4-[(di(4-methoxy-3,5-dimethylphenyl)phosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one-borane
(CLMPL-S)
[0060] The target compound was obtained from (3aR,4S,5S,6aS)-5-di(4-methoxy-3,5-dimethylphenyl)phosphanyl]-4-[(di(4-methoxy-3,5-dimethylphenyl)phosphanyl)methyl]hexahydrocyclopenta[b]furan-2-one-borane
complex (Compound 9) in the same manner as that of Example 9 at a yield of 76%.
1H NMR (CDCl
3, 300MHz): δ 7.08-6.94 (m, 6H), 6.82 (d, J=7.8Hz, 2H), 4.99 (t, J=6.0Hz, 1H), 3.70
(s, 3H), 3.69 (s, 3H), 3.68 (s, 3H), 3.67 (s, 3H), 3.31 (brs, 1H), 2.91-2.81 (m, 2H),
2.67-2.63 (m, 1H), 2.44-1.68 (m, 3H), 2.24 (s, 6H), 2.21 (s, 12H), 2.07 (s, 6H)
[α]
D20 = -104.76 (c=1.03, toluene)
Example 16: Preparation of [Rh(CLPL-S)(COD)]BF4 (COD = 1,5-cyclooctadiene)
[0061] To a 10 mL-recovery flask were added [RhCl(COD)]
2 (0.12 g, 0.23 mmol) and silver tetrafluoroborate (0.1 g, 0.49 mmol), and the atmosphere
in the flask was substituted with nitrogen. The mixture was added with 1 mL of acetone,
stirred for 15 minutes, then added with a solution of CLPL-S (0.47 mmol) in 3 mL of
acetone, and stirred for 30 minutes. The precipitated solid was collected by filtration,
and then the filtrate was evaporated under reduced pressure until the remaining volume
became about 1 mL. The remaining filtrate was added with 30 mL of dehydrated diethyl
ether to cause crystallization, and the precipitated solid was collected by filtration
and dried to obtain the metal complex as orange solid (yield: 99%).
31PNMR (160 MHz, acetone-d
6): δ 26.5(dd, 46.9, 143.9Hz), 20.2(dd, 46.9, 145.5Hz)
Example 17: Preparation of [Rh(CLPDO-S)(COD)]BF4
[0062] The target compound was obtained in the same manner as that of Example 16 except
that CLPD was used instead of CLPL-S (yield: 93%).
31PNMR (160 MHz, acetone-d
6): δ 30.5(dd, 46.7, 141.5Hz), 20.1(dd, 46.7, 142.8Hz)
Example 18: Preparation of [Rh(CLPTO-S)(COD)]BF4
[0063] The target compound was obtained in the same manner as that of Example 16 except
that CLPTO-S was used instead of CLPL-S (yield: 76%).
31PNMR (160 MHz, acetone-d
6): δ 30.6(dd, 46.9, 142.3Hz), 20.2(dd, 46.9, 143.9Hz)
Example 19: Preparation of [Rh(CLPTM-S)(COD)]BF4
[0064] The target compound was obtained in the same manner as that of Example 16 except
that CLPTM-S was used instead of CLPL-S (yield: 67%).
31PNMR (160 MHz, acetone-d6): δ 31.0(ddd, 22.0, 46.7, 142.9Hz), 20.3(ddd, 23.3, 46.7,
142.8Hz)
Example 20: Preparation of [Rh(CLPOX-S)(COD)]BF4
[0065] The target compound was obtained in the same manner as that of Example 16 except
that CLPOX-S was used instead of CLPL-S (yield: 82%).
31PNMR (160 MHz, acetone-d
6): δ 30.6(dd, 45.9, 141.5Hz), 20.2(dd, 46.0, 142.8Hz)
Example 21: Preparation of [Rh(CLPF-R)(COD)]BF4
[0066] The target compound was obtained in the same manner as that of Example 16 except
that CLPF-R was used instead of CLPL-S (yield: 89%).
31PNMR (160 MHz, acetone-d
6): δ 26.3(dd, 46.6, 142.8Hz), 19.9(dd, 45.4, 144.2Hz)
Example 22: Preparation of [Rh(CLMPL-S)(COD)]BF4
[0067] The target compound was obtained in the same manner as that of Example 16 except
that CLMPL-S was used instead of CLPL-S (yield: 72%).
Example 23: Preparation of optically active N-acetylphenylalanine using rhodium metal
complex catalyst
[0068]

[0069] The atmosphere in a 25 mL-recovery flask was substituted with nitrogen, and 3 mL
of deoxygenized methanol and triethylamine (20.9 µL, 0.15 mmol) were added to the
flask as the reaction solvent. α-Acetamidocinnamic acid (0.20 g, 0.98 mmol) and [Rh(CLPL-S)(COD)]BF
4 (3.95 mg, 0.0049 mmol) were weighed in a 50 mL-Pyrex (registered trade name) test
tube for autoclaving, the tube was put into an autoclave together with a stirrer in
the tube, and the atmosphere in the autoclave was substituted with nitrogen. The reaction
solvent in a volume of 2 mL was added to the mixture, the atmosphere in the autoclave
was sufficiently substituted with hydrogen, and then pressurized with 2 MPa of hydrogen,
and the reaction mixture was stirred at 40°C for 22 hours. After 22 hours, the atmosphere
in the autoclave was returned to ordinary pressure, and the reaction mixture was concentrated
in an evaporator. The concentrated residue was added with 5 mL of 2 M aqueous sodium
hydroxide for dissolution, and the solution was washed with 5 mL of ethyl acetate.
The aqueous layer was separated, and added with diluted hydrochloric acid until pH
of the aqueous layer became lower than 2, and the produced oil was extracted with
10 mL of ethyl acetate. The organic layer was concentrated in an evaporator to obtain
(R)-N-acetylphenylalanine quantitatively.
1H NMR (300MHz, CD
3OD): δ 7.25-7.12 (m, 5H), 4.58 (dd, J=4.8, 8.9Hz, 1H), 3.15 (dd, J=5.1, 13.8Hz, 1H),
2.89 (dd, J=9.0, 13.8Hz, 1H), 1.89 (s, 3H)
[0070] The resulting (R)-N-acetylphenylalanine in an amount of 2 mg was dissolved in 0.5
mL of methanol and 0.5 mL of dichloromethane, and the solution was added with a 10%
solution of trimethylsilyldiazomethane in n-hexane until the solution colored in yellow
to obtain the methyl ester compound. The solvent was concentrated in an evaporator,
and the residue was dissolved in 1 mL of a mixture of n-hexane and 2-propanol (9:1).
HPLC analysis of this solution under the following conditions revealed that the compound
consist of 95%ee of the (R)-isomer.
Analysis conditions: Chiralcel-OD produced by Daicel Chemical Industries, Ltd., mobile
phase: n-hexane/2-propanol = 9/1, flow rate: 1.0 mL/min., detector wavelength: 220
nm, column temperature: 40°C, injection: 2µL, R.T.: R-isomer = 8.4 min., S-isomer
= 9.8 min. Examples 24 to 28: Preparation of optically active N-acetylphenylalanine
using rhodium metal complex catalyst
[0071] The target compounds were synthesized in the same manner as that of Example 23 except
for the metal complex catalyst.
Table 1
| Example |
Metal complex catalyst |
Steric configuration |
%ee |
| 24 |
[Rh(CLPDO-S)(COD)]BF4 |
(R) |
87 |
| 25 |
[Rh(CLPTO-S)(COD)]BF4 |
(R) |
85 |
| 26 |
[Rh(CLPTM-S)(COD)]BF4 |
(R) |
85 |
| 27 |
[Rh(CLPOX-S)(COD)]BF4 |
(R) |
83 |
| 28 |
[Rh(CLMPL-S)(COD)]BF4 |
(R) |
95 |
Examples 29 to 30: Preparation of optically active N-acetylphenylalanine using rhodium
metal complex catalyst
[0072] α-Acetamidocinnamic acid (0.20 g, 0.98 mmol), [RhCl(COD)]
2 (1.2 mg, 0.0025 mmol) and a ligand (0.005 mmol) were weighed in a 50 mL-Pyrex (registered
trade name) test tube for autoclaving, and a stirrer was put into the tube. This test
tube was set in a 50 mL-autoclave, and the atmosphere in the autoclave was substituted
three times with nitrogen. The reaction mixture was added with 2 mL of degassed methanol,
the atmosphere in the autoclave was sufficiently substituted with hydrogen, and then
pressurized with 0.8 MPa of hydrogen, and the reaction mixture was stirred at 40°C
for 22 hours. The post-treatment after the reaction was performed in the same manner
as that of Example 23.
Table 2
| Example |
Ligand |
Steric configuration |
%ee |
| 29 |
CLPDO-S |
(R) |
87 |
| 30 |
CLPF-R |
(S) |
98 |
Examples 31 to 36: Preparation of optically active 3-methoxycarbonyl-4-cyclohexylbutyric
acid using rhodium metal complex catalyst
[0073]

[0074] 2-Cyclohexylmethylidenesuccinic acid 1-methyl ester (0.22 g, 1.0 mmol) and each metal
complex catalyst (0.005 mmol) were weighed in a Pyrex (registered trade name) test
tube for autoclaving and the tube was put into a 50 mL-autoclave together with a stirrer
in the tube, and then the atmosphere in the autoclave was substituted with nitrogen.
The mixture was added with 2 mL of deoxygenized methanol, and after the atmosphere
in the autoclave was sufficiently substituted with hydrogen, and then pressurized
with 0.5 MPa of hydrogen, the mixture was stirred at 45°C for 18 hours. After 18 hours,
the atmosphere of the autoclave was returned to ordinary pressure, and the reaction
mixture was concentrated in an evaporator. The concentrated residue was added with
5 mL of 2 M aqueous sodium hydroxide for dissolution, and the solution was washed
with 5 mL of ethyl acetate. The aqueous layer was separated, and added with diluted
hydrochloric acid until pH of the aqueous layer became lower than 2, and the produced
oil was extracted with 10 mL of ethyl acetate. The organic layer was concentrated
in an evaporator to quantitatively obtain optically active cyclohexylmethylsuccinic
acid 1-methyl ester.
1H NMR (300MHz, CDCl
3): δ 3.70 (s, 3H), 2.97-2.87 (m, 1H), 2.73 (dd, J=9.5, 16.8Hz, 1H), 2.47 (dd, J=4.8,
16.8Hz, 1H), 1.79-1.53 (m, 6H), 1.44-1.07 (m, 5H), 0.95-0.82 (m, 2H)
[0075] The resulting optically active 3-methoxycarbonyl-4-cyclohexylbutyric acid in an amount
of 9.5 mg was dissolved in 5 mL of benzene, and added with 27 µL of trifluoroacetic
acid anhydride, and the mixture was stirred at 40°C for 1 hour. The reaction mixture
was added with 0.88 mL of a 213 mM solution of phenol in benzene, and the mixture
was further stirred for 20 minutes. The reaction mixture was transferred to a separatory
funnel, washed with 5 mL of 2 M aqueous sodium hydroxide, and dried over anhydrous
sodium sulfate. After the drying agent was removed by filtration, the reaction mixture
was concentrated in an evaporator, and the residue was dissolved in 1 mL of a mixture
of n-hexane and 2-propanol (99:1).
Analysis conditions: Chiralcel-OD produced by Daicel Chemical Industries, Ltd., mobile
phase: n-hexane/2-propanol = 99/1, flow rate: 1.0 mL/min., detector wavelength: 254
nm, column temperature: 40°C, injection: 2µL, R.T.: S-isomer = 11.9 min., R-isomer
= 29.2 min.
Table 3
| Example |
Metal complex catalyst |
Steric configuration |
%ee |
| 31 |
[Rh(CLPL-S)(COD)]BF4 |
(R) |
87 |
| 32 |
[Rh(CLPDO-S)(COD)]BF4 |
(R) |
96 |
| 33 |
[Rh(CLPTO-S)(COD)]BF4 |
(R) |
96 |
| 34 |
[Rh(CLPTM-S)(COD)]BF4 |
(R) |
95 |
| 35 |
[Rh(CLPOX-S)(COD)]BF4 |
(R) |
95 |
| 36 |
[Rh(CLPF-R) (COD)]BF4 |
(S) |
87 |
Examples 37 to 38: Preparation of optically active 3-methoxycarbonyl-5-methylcaproic
acid using rhodium metal complex catalyst
[0076]

[0077] The preparation was performed in the same manner as those of Example 31 to 36 except
that isobutylidenesuccinic acid 1-methyl ester was used as the substrate. 3-Methoxycarbonyl-5-methylcaproic
acid
1H NMR (300MHz, CDCl
3): δ 3.66 (s, 3H), 2.90-2.81 (m, 1H), 2.60 (dd, J=9.3, 16.8Hz, 1H), 2.47 (dd, J=5.3,
16.8Hz, 1H), 1.62-1.48 (m, 2H), 1.36-1.26 (m, 1H), 0.91 (dd, J=6.6, 11.1Hz, 6H)
[0078] The resulting optically active 3-methoxycarbonyl-5-methylcaproic acid in an amount
of 10 mg was dissolved in 0.5 mL of methanol and 0.5 mL of dichloromethane, and the
solution was added with a 10% solution of trimethylsilyldiazomethane in n-hexane until
the solution colored in yellow to obtain the methyl ester compound. The solvent was
concentrated in an evaporator, and the residue was dissolved in 1 mL of a mixture
of n-hexane and 2-propanol (99.5:0.5). This solution was analyzed by HPLC under the
following conditions.
Analysis conditions: Chiralcel-OD produced by Daicel Chemical Industries, Ltd., mobile
phase: n-hexane/2-propanol = 99.5/0.5, flow rate: 1.0 mL/min., detector wavelength:
220 nm, column temperature: 40°C, injection: 2 µL, R.T.: S-isomer = 8.9 min., R-isomer
= 21.0 min.
Table 4
| Example |
Metal complex catalyst |
Steric configuration |
%ee |
| 37 |
[Rh(CLPL-S)(COD)]BF4 |
(R) |
85 |
| 38 |
[Rh(CLPDO-S)(COD)]BF4 |
(R) |
96 |
Examples 39 to 42: Preparation of optically active 3-methoxycarbonyl-5-phenylvaleric
acid using rhodium metal complex catalyst
[0079]

[0080] The preparation was performed in the same manner as those of Examples 21 to 26 except
that cinnamilidenesuccinic acid 1-methyl ester was used as the substrate. 3-Methoxycarbonyl-5-phenylvaleric
acid
1H NMR (300MHz, CDCl
3): δ 7.30-7.14 (m, 5H), 3.72 (s, 3H), 2.88-2.82 (m, 1H), 2.76 (dd, J=9.3, 16.5Hz,
1H), 2.61 (t, 7.1Hz, 2H), 2.46 (dd, J=4.5, 16.5Hz, 1H), 1.73-1.54 (m, 4H)
[0081] The resulting optically active 3-methoxycarbonyl-5-phenylvaleric acid in an amount
of 2 mg was dissolved in 0.5 mL of methanol and 0.5 mL of dichloromethane, and added
with a 10% solution of trimethylsilyldiazomethane in n-hexane until the solution colored
in yellow to prepare the methyl ester compound. The solvent was concentrated in an
evaporator, and the residue was dissolved in 1 mL of a mixture of n-hexane and 2-propanol
(95:5). This solution was analyzed by HPLC under the following conditions.
Analysis conditions: Chiralcel-OD produced by Daicel Chemical Industries, Ltd., mobile
phase: n-hexane/2-propanol = 95/5, flow rate: 1.0 mL/min., detector wavelength: 220
nm, column temperature: 40°C, injection: 2µL, R.T.: S-isomer = 6.8 min., R-isomer
= 9.0 min.
Table 5
| Example |
Metal complex catalyst |
Steric configuration |
%ee |
| 39 |
[Rh(CLPDO-S)(COD)]BF4 |
(R) |
82 |
| 40 |
[Rh(CLPTO-S)(COD)]BF4 |
(R) |
76 |
| 41 |
[Rh(CLPTM-S)(COD)]BF4 |
(R) |
72 |
| 42 |
[Rh(CLPOX-S)(COD)]BF4 |
(R) |
80 |
Examples 43 to 45: Preparation of optically active 3-phenylcyclohexanone using rhodium
metal complex catalyst
[0082]

[0083] To a 25-mL three-neck flask were added Rh(acac)(cod) (6.8 mg, 21.8 µmol) and PhB(OH)
2 (445 mg, 3.65 mmol), and the atmosphere in the system was substituted with argon.
The mixture was added with 3.6 mL of a solution of each ligand (21.8 µmol) in anhydrous
dioxane and 2-cyclohexenone (0.073 mL, 0.73 mmol). The mixture was stirred at room
temperature for 15 minutes, and added with water (0.18 mL). The reaction mixture was
stirred at 100°C for 3 hours, then added with 9 mL of water, and extracted twice with
9 mL of diethyl ether. The organic layers were combined, washed with 9 mL of saturated
sodium chloride solution, and concentrated in an evaporator. The residue was treated
by silica gel column chromatography (toluene:ethyl acetate = 2:1) to obtain 3-phenylcyclohexane
as colorless oil. The resulting optically active 3-phenylcyclohexanone in an amount
of 2 mg was dissolved in 1 mL of a mixture of n-heptane and 2-propanol (99:2). This
solution was analyzed by HPLC under the following conditions.
Analysis conditions: Chiralcel-ODH produced by Daicel Chemical Industries, Ltd., mobile
phase: n-heptane:2-propanol = 99:2, flow rate: 1.0 mL/min., detector wavelength: 215
nm, column temperature: 40°C, injection: 2µL, R.T.: S-isomer = 36.7 min., R-isomer
= 39.6 min.
Table 6
| Example |
Ligand |
Steric configuration |
%ee |
| 43 |
CLPL-S |
(S) |
5 |
| 44 |
CLPF-R |
(R) |
31 |
| 45 |
CLPDO-S |
(S) |
23 |
Examples 46 to 48: Preparation of optically active 2-benzylamino-1-(4-fuluorophenyl)ethanol
using rhodium metal complex catalyst
[0084]

[0085] In a 25 mL-recovery flask, each ligand (0.050 mmol) and [RhCl(COD)]
2 (11.2 mg, 0.227 mmol) were weighed, and the atmosphere in the flask was substituted
with argon. The mixture was added with 20 mL of degassed methanol and triethylamine
(0.13 mL, 0.91 mmol) and made into a solution by dissolution to prepare a catalyst
solution. Separately, 2-benzylamino-1-(4-fuluorophenyDethanone hydrochloride (254
mg, 0.908 mmol) was weighed in a Pyrex (registered trade name) test tube for autoclaving,
the test tube was set in a 50-mL autoclave together with a stirrer in the tube, and
the atmosphere in the autoclave was substituted with nitrogen five times. The reaction
mixture was added with 2 mL of the prepared catalyst solution (corresponding to 0.00454
mmol of catalyst), the atmosphere in the autoclave was sufficiently substituted with
hydrogen, and then pressurized with 1.5 MPa of hydrogen, and the reaction was allowed
at 50°C for 22 hours. The solvent of the reaction mixture was evaporated, and the
residue was transferred to a separatory funnel with dissolving it in 20 mL of water
and 10 mL of toluene, and the aqueous layer was separated. pH of the aqueous layer
was made higher than 11 with 2 M aqueous sodium hydroxide, and the produced oil was
extracted with 10 mL of ethyl acetate. The organic layer was concentrated in an evaporator
to quantitatively obtain optically active 2-benzylamino-1-(4-fuluorophenyl)ethanol.
1H NMR (300MHz, CD
3OD): δ 7.53-7.40 (m, 7H), 7.14-7.07 (m, 2H), 4.98 (dd, 3.3, 10.2Hz, 1H), 4.27 (s,
3H), 3.22-3.03 (m, 2H)
[0086] The resulting optically active 2-benzylamino-1-(4-fuluorophenyl)ethanol weighed in
an amount of 2 mg was dissolved in 1 mL of a mixture of n-hexane:2-propanol:diethylamine
= 98:2:0.1, and HPLC was performed under the following conditions.
Analysis conditions: CHIRALPAK AS-H produced by Daicel Chemical Industries, Ltd.,
n-hexane:2-propanol:diethyl amine = 98:2:0.1, flow rate: 1.0 mL/min., detector wavelength:
265 nm, column temperature: 35°C, injection: 2 µL, R.T.: S-isomer = 21.1 min., R-isomer
= 25.3 min.
Table 7
| Example |
Ligand |
Steric configuration |
%ee |
| 46 |
CLPL-S |
(S) |
48 |
| 47 |
CLPDO-S |
(S) |
42 |
| 48 |
CLPF-R |
(R) |
51 |
Examples 49 to 62: Preparation of β-acetamidoalanine esters using rhodium metal complex
catalyst
[0087]

[0088] Each substrate for reduction (1.0 mmol) and each metal complex (0.005 mmol) were
weighed in a Pyrex (registered trade name) test tube for autoclaving, the tube was
set in a 50-mL autoclave together with a stirrer in the tube, and the atmosphere in
the autoclave was substituted with nitrogen. The reaction mixture was added with 2
mL of methanol, the atmosphere in the autoclave was sufficiently substituted with
hydrogen, and then pressurized with 2 MPa of hydrogen, and the reaction was allowed
at 45°C for 17 hours. After the reaction, the reaction mixture was added with 0.02
g of activated carbon, and stirred for 30 minutes, and after the activated carbon
was removed, the reaction mixture was concentrated in an evaporator to quantitatively
obtain each β-acetamidoalanine ester.
[0089] The resulting β-acetamidoalanine ester in an amount of 2 mg was dissolved in 1 mL
of methanol, and analyzed by GC or HPLC under the following conditions. 3-Acetylaminobutanoic
acid ethyl ester (R = Me, R' = Et)
Analysis conditions: column produced by SPELCO, β-DEX 325, column temperature: 140°C,
injection temperature: 220°C, detector temperature: 300°C, mobile phase: 50 kPa of
helium, split ratio: 50:1, FID detector, injection: 5 µL, R.T.: S-isomer = 25.5 min.,
R-isomer = 26.4 min.
1H NMR (300MHz, CDCl
3): δ 6.15 (brs, 1H), 4.39-4.31 (m, 1H), 4.21 (q, 7.2Hz, 2H), 2.52 (dd, 2.8, 5.3Hz,
2H), 1.96 (s, 3H), 1.27 (t, J=7.2Hz, 3H), 1.23 (d, J=6.6Hz, 3H)
3-Acetylaminopentanoic acid methyl ester (R = Et, R' = Me)
Analysis conditions: column produced by SPELCO, ß-DEX 325, column temperature: 120°C,
injection temperature: 220°C, detector temperature: 300°C, mobile phase: 50 kPa of
helium, split ratio: 50:1, FID detector, injection: 5 µL, R.T.: S-isomer = 54.4 min.,
R-isomer = 56.0 min.
1H NMR (300MHz, CDCl
3): δ 6.09 (brs, 1H), 4.19-4.12 (m, 1H), 3.69 (s, 3H), 2.54 (dd, J=3.8, 5.0Hz, 2H),
1.99 (s, 3H), 1.62-1.51 (m, 2H), 0.92 (t, J=7.5Hz, 3H)
3-Acetylaminohexanoic acid ethyl ester (R = n-Pr, R' = Et)
Analysis conditions: Chiralcel OC produced by Daicel Chemical Industries, Ltd., n-hexane/2-propanol
= 9/1, 0.5 mL/min., 210 nm, 30°C, R.T.: S-isomer = 25.4 min., R-isomer = 30.0 min.
1H NMR (300MHz, CDCl
3): δ 6.09 (d, J=7.8Hz, 1H), 4.30-4.19 (m, 1H), 4.15 (q, J=7.2Hz, 2H), 2.52 (ddd, J=5.1,
15.8, 23.5Hz, 2H), 1.97 (s, 3H), 1.61-1.29 (m, 4H), 1.25 (t, J=6.8Hz, 3H), 0.91 (t,
J=7.4Hz, 3H)
3-Acetylamino-3-phenylpropanoic acid ethyl ester (R = Ph, R' = Et)
Analysis conditions: Chiralcel OD by Daicel Chemical Industries, Ltd., n-hexane/2-propanol
= 95/5, 1.0 mL/min., 220 nm, 40°C, R.T.: R-isomer = 22.5 min., S-isomer = 26.0 min.
1H NMR (300MHz, CDCl
3): δ 7.36-7.23 (m, 5H), 6.62 (d, J=7.8Hz, 1H), 5.46-5.40 (m, 1H), 4.06 (q, J=7.8Hz,
2H), 2.96-2.78 (m, 2H), 2.03 (s, 3H), 1.16 (t, J=7.2Hz, 3H)
Table 8
| Example |
Metal complex catalyst |
R |
R' |
E/Z |
Steric configuration |
%ee |
| 49 |
[Rh(CLPL-S)(COD)]BF4 |
Me |
Et |
Z |
(R) |
24 |
| 50 |
[Rh(CLPDO-S)(COD)]BF4 |
Me |
Et |
Z |
(S) |
47 |
| 51 |
[Rh(CLPL-S)(COD)]BF4 |
Me |
Et |
E |
(S) |
66 |
| 52 |
[Rh(CLPDO-S)(COD)]BF4 |
Me |
Et |
E |
(S) |
89 |
| 53 |
[Rh(CLPL-S)(COD)]BF4 |
n-Pr |
Et |
Z |
(S) |
74 |
| 54 |
[Rh(CLPDO-S)(COD)]BF4 |
n-Pr |
Et |
Z |
(S) |
22 |
| 55 |
[Rh(CLPL-S)(COD)]BF4 |
n-Pr |
Et |
E |
(S) |
69 |
| 56 |
[Rh(CLPDO-S)(COD)]BF4 |
n-Pr |
Et |
E |
(S) |
94 |
| 57 |
[Rh(CLPL-S)(COD)]BF4 |
Et |
Me |
Z |
(S) |
6 |
| 58 |
[Rh(CLPDO-S)(COD)]BF4 |
Et |
Me |
Z |
(S) |
57 |
| 59 |
[Rh(CLPL-S)(COD)]BF4 |
Et |
Me |
E |
(S) |
76 |
| 60 |
[Rh(CLPDO-S)(COD)]BF4 |
Et |
Me |
E |
(S) |
95 |
| 61 |
[Rh(CLPL-S)(COD)]BF4 |
Ph |
Et |
Z |
(R) |
27 |
| 62 |
[Rh(CLPDO-S)(COD)]BF4 |
Ph |
Et |
Z |
(R) |
66 |
| Me: methyl group, Et: ethyl group, n-Pr: n-propyl group, Ph: phenyl group |
Example 63: Preparation of [Ir(COD)(CLPDO-S)]BF4
[0090] The preparation of the iridium metal complex was performed in the same manner as
that of Example 16. To a 10 mL-recovery flask were added [IrCl(COD)]
2 (86.7 mg, 0.13 mmol) and silver tetrafluoroborate (52.7 mg, 0.26 mmol), and the atmosphere
in the flask was substituted with nitrogen. The mixture was added with 2 mL of degassed
ethanol, stirred for 10 minutes, and then filtered, and the residue was washed with
2 mL of ethanol. The filtrate and the wash were combined, added to a 25 mL-recovery
flask containing CLPDO-S (0.13 g, 0.26 mmol) under a nitrogen atmosphere, and the
mixture was stirred for 10 minutes. The reaction mixture was evaporated under reduced
pressure until the remaining volume became about 1 mL, the remaining reaction mixture
was added with 20 mL of diethyl ether, and the precipitated solid was collected by
filtration and dried to obtain the title compound as reddish orange solid (0.22 g,
yield: 94%).
Examples 64 to 66: Preparation of N-benzyl-1-phenylethylamine using rhodium or iridium
metal complex catalyst
[0091]

[0092] N-Benzyl-1-phenylethanimine (0.11 g, 0.5 mmol) and each metal complex (0.005 mmol)
were weighed in a Pyrex (registered trade name) test tube for autoclaving, the tube
was set in a 50-mL autoclave together with a stirrer in the tube, and the atmosphere
in the autoclave was substituted with nitrogen. The mixture was added with 2 mL of
methanol and Et
3N (14 µL, 0.1 mmol), the atmosphere in the autoclave was sufficiently substituted
with hydrogen, and then pressurized with 5.0 MPa of hydrogen, and the reaction was
allowed at 40°C for 24 hours. After the reaction, the reaction mixture was added with
0.02 g of activated carbon and stirred for 30 minutes, and after the activated carbon
was removed, the reaction mixture was concentrated in an evaporator to quantitatively
obtain optically active N-benzyl-1-phenylethylamine.
1H NMR (300MHz, CDCl
3): δ 7.35-7.21 (m, 10H), 3.81 (q, 6.6Hz, 1H), 3.63 (dd, J=7.2, 21.9Hz, 2H), 1.37 (d,
J=6.6Hz, 3H)
[0093] The resulting N-benzyl-1-phenylethylamine was analyzed by HPLC under the following
conditions.
Analysis conditions: Chiralcel-OJ produced by Daicel Chemical Industries, Ltd., mobile
phase: n-hexane:2-propanol:diethylamine = 200:1:0.1, flow rate: 0.7 mL/min., detector
wavelength: 220 nm, column temperature: 40°C, injection: 2 µL, R.T.: S-isomer = 13.5
min., R-isomer = 14.9 min.
Table 9
| Example |
Metal complex catalyst |
Steric configuration |
%ee |
| 64 |
[Rh(CLPL-S)(COD)]BF4 |
(R) |
11 |
| 65 |
[Rh(CLPDO-S)(COD)]BF4 |
(R) |
29 |
| 66 |
[Ir(CLPDO-S)(COD)]BF4 |
(S) |
23 |