Method for producing an alcohol

The present invention provides a method for producing a alcohol including an optically active alcohol by hydrogenating a carbonyl compound in the presence of a homogeneous catalyst, a base and a nitrogen-containing organic compound. Thus, the reaction employs an inexpensive catalyst and proceeds in high yield and high efficiency.

FIELD OF THE INVENTION 
The present invention relates to a method for producing an alcohol. More 
particularly, the present invention relates to a novel method for 
efficient production at a high yield of alcohol useful as medical drugs, 
agricultural chemicals, various other chemicals or raw material or a 
synthetic intermediate thereof, ant to a new method for producing 
optically active alcohol, which is excellent in practicability and useful 
in various uses including synthetic intermediates of medical drugs and 
material for liquid crystal. 
PRIOR ART AND PROBLEMS 
Method for producing alcohol have been conventionally known, which comprise 
hydrogenation of carbonyl compound, by using a homogeneous catalyst 
system, thereby obtaining corresponding alcohol, including fort example: 
(1) a method using a ruthenium complex as described in Comprehensive 
Organometallic Chemistry, Vol 4, p. 931 (1982), Eds, G.Wilkinson, F. G. A. 
Stone and E. W. Abel; (2) methods using a rhodium complex as described in 
Inorg. Nucl. Chem. Letters, Vol. 12, p. 865(1976); J. Organomet. Chem., 
Vol. 129, p. 239 (1997); Chem. Letters, P. 261 (1982); and Tetrahedron 
Letters, Vol 35, p, 4963 (1994); and (3) a method using an iridium complex 
as described in J. An. Chem. Soc., Vol. 115, p. 3318 (1993). 
However, these conventional methods require as a catalyst any of such 
metals as ruthenium, rhodium, iridium, palladium and platinum which are 
relatively expensive nobel metals, and the metals have problems in that 
the hydrogenation activity is low and the reaction requires specific 
conditions including a relatively high temperature or a high hydrogen 
pressure, thus making these materials unsuitable for practical use. 
Additionally, the conventionally known methods for asymmetrically 
synthesizing optically active alcohol include: 1) a method using an enzyme 
such as baker's yeast, and 2) a method for asymmetric hydrogenation of a 
carbonyl compound by the use of a metal complex catalyst. Particularly, 
regarding the latter method, many cases of asymmetric catalytic reactions 
have been reported, including for example: (1) a method of asymmetric 
hydrogenation of a carbonyl compound having a functional group using 
optically active ruthenium catalyst described in detail in Asymmetric 
Catalysis In Organic Synthesis, p. 56-82 (1994) ed. R. Noyori; (2) a 
method based on hydrogen transfer type reduction reaction through 
asymmetric complex catalysis of ruthenium, rhodium and iridium described 
in Chem. Rev., Vol. 92, p. 1051-1069 (1992); (3) a method of asymmetric 
hydrogenation using a nickel catalyst prepared by modifying tartaric acid 
described in Petr. Chem., p. 882-831 (1980) and Advances in Catalysis, 
Vol. 32, p. 215 (1983) ed. Y. Izumi; (4) a method based on asymmetric 
hydrosilation as described in Asymmetric Synthesis, vol 5, Chap. 4 (1985) 
ed. J. D. Morrison and J. Organomet. Chem., Vol. 346, p. 413-424 (1988); 
and a method of borane-reduction in the presence of chiral ligands 
described in J. Chem. Soc., Perkin Trans. 1, p. 2039-2044 (1985) and J. 
Am. Chem. Soc., Vol. 109, p. 5551-5553 (1987). 
Although the method using an enzyme gives alcohol with a relatively high 
optical purity, however, it is defective in that kinds of reaction 
substrates are limited, and the resultant alcohol is limited to one having 
a specific absolute configuration. In the case of the method using an 
asymmetric hydrogenation catalyst based on a transition metal, while 
realizing production of optically active alcohol with a high selectivity 
for such a substrate as keto acid, for example, it has a drawback of a low 
reaction rate, and in addition, the method is not valid for relatively 
simple carbonyl compounds having no functional group in the molecule. 
For these reasons, there has been a demand for achievement of a new 
synthetic method for producing an optically active alcohol having a high 
generality and using a highly active catalyst. 
SUMMARY OF THE INVENTION 
The present invention has therefore an object to solve these problem in the 
prior arts, and provide a novel method for producing an alcohol through a 
hydrogenation reaction with a high efficiency by the use of an inexpensive 
catalyst system. 
As means to solve the above-mentioned problems, the present invention 
provides a method for producing an alcohol, which comprises the step of 
subjecting a carbonyl compound to a hydrogenation reaction in the presence 
of a homogeneous hydrogenation catalyst, a base, and a nitrogen-containing 
organic compound. 
Particularly, in the present invention, a catalyst of a VIII-group metal 
complex is used as a catalyst of a higher activity. A base and a 
nitrogen-containing organic compound are also used in addition to the 
VIII-group metal complex. 
As the carbonyl compound which is the raw material for producing an alcohol 
through hydrogenation reaction, for example, a compound expressed by the 
following formula (1): 
##STR1## 
(where, R.sup.1 and R.sup.2 are aromatic monocyclic or polycyclic 
hydrocarbon groups or hetero-monocyclic or polycyclic groups containing 
heteroatoms, which may have the same or different substitution groups or a 
saturated or unsaturated chain or cyclic hydrocarbon group, any one on 
which may be hydrogen atom. R.sup.1 and R.sup.2 also may form a cyclic 
group by themselves) may appropriately be used. 
The present invention also provides a method for producing an optical 
active alcohol, which comprises the step of subjecting a carbonyl compound 
expressed by the following general formula (2): 
##STR2## 
(where, R.sup.3 is an aromatic monocyclic or polycyclic hydrocarbon group, 
a saturated or unsaturated aliphatic or cyclo-hydrocarbon group, or a 
hetero-monocyclic or polycyclic group containing heteroatoms, which may 
have a substitution group R.sup.4 ; and R.sup.4 is a saturated or 
non-saturated chain, cyclic or aromatic cyclic hydrocarbon or heterocyclic 
group, which may have hydrogen or a substitution group. R.sup.3 and 
R.sup.4 also may form a cyclic groups by themselves.) to a hydrogenation 
reaction in the presence of an asymmetric hydrogenation catalyst of a 
transition metal, a base and a optically active nitrogen-containing 
compound thereby producing optically active alcohol expressed by the 
following general formula (3): 
##STR3## 
(where, R.sup.3 and R.sup.4 are the same organic groups as above). 
DETAILED DESCRIPTION OF THE INVENTION 
Regarding the present invention for a method of producing an alcohol, the 
substitution group in the case of formula (1), any of various organic 
groups which never impairs hydrogenation reaction, such as hydrocarbon 
group, halogen group, hydroxy group, alkoxy group, carboxyl group, ester 
group, amino group and heterocyclic group may appropriately be used. 
As R.sup.1 and R.sup.2, applicable ones include hydrogen atom; aromatic 
monocyclic or polycyclic groups such as phenyl group, 2-methylphenyl, 
2-ethylphenyl, 2-isopropylphenyl, 2-tert-butylphenyl, 2-methoxyphenyl, 
2-chlorophenyl, 2-vinylphenyl, 3-methylphenyl, 3-ethylphenyl, 
3-isopropylphenyl, 3-methoxyphenyl, 3-chlorophenyl, 3-vinylphenyl, 
4-methylphenyl, 4-ethylphenyl, cumenyl, mesityl, xylyl, 1-naphthyl, 
2-naphthyl, anthryl, phenanthryl, and indenyl; heteromonocyclic or 
polycyclic groups such as thienyl, furyl, pyranyl, xanthenyl, pyridyl, 
pyrrolidyl, imidazolyl, indolyl, and phenanthrolyl; and ferrocenyl group, 
cyclic or acylic hydrocarbon groups, for example, alkyl groups such as 
methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl, cycloalkyl groups 
such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl, and 
hydrocarbons containing unsaturated groups such as benzyl, vinyl and 
allyl. 
In case of cyclic group formed by connecting R.sup.1 and R.sup.2, for 
example, saturated or unsaturated cyclo-aliphatic groups providing cyclic 
ketone such as cyclopentanone, cyclohexanone, cycloheptanone, 
cyclopentenone, cyclohexenone, cycloheptenone; substituted saturated or 
unsaturated cyclo-aliphatic groups having substitution groups selected 
from alkyl, aryl, unsaturated alkyl, aliphatic or cyclo-aliphatic group 
containing hetero atom; are mentioned. 
The VIII-group metals include rhodium (Rh), ruthenium (Ru), iridium (Ir), 
palladium(Pd), and platinum(Pt). Particularly, ruthenium(Ru) is used for a 
high activity in the present invention for producing an alcohol. 
These VIII-groups metals are used in the form of soluble complex catalyst 
as homogeneous catalyst, For example, this catalyst can be expressed by 
the following general formula (4). 
EQU MXmLn (4) 
(where, M is a VIII-group metal; X is halogen atom, carboxyl group, alkoxy 
group or hydroxy group; and L is phosphine, olefin, diolefin, cycloolefin, 
CO, arsine, amine or other organic ligand) 
For example, phosphine ligand can be expressed by a general formula 
PR.sup.5 R.sup.6 R.sup.7, where R.sup.5, R.sup.6, and R.sup.7 may be the 
same or different, and are aliphatic groups, alicyclic groups or aromatic 
groups, or may be bidentate phosphine ligands. Applicable phosphine 
ligands include, for example, such tert-phosphines as trimethylphosphine, 
triethylphosphine, tributyl-phosphine, triphenylphosphine, 
tricyclohexylphosphine, tri(p-tolyl)phosphine, diphenylmethylphosphine, 
dimethylphenylphosphine, and bidentate tert-phosphine compounds such as 
bis-diphenyl-phosphinoethane, bis-diphenylphosphinopropane, 
bis-diphenylphosphinobutane, bis-dimethylphosphinoethane, and 
bis-dimethylphosphinopropane. 
As complex based on ligand described above, preferable examples include 
complexes of ruthenium, rhodium, iridium, palladium and platinum. Among 
others, ruthenium complex has a high activity More specifically, 
applicable complexes include RuCl.sub.2 P(C.sub.6 H.sub.5).sub.3 !.sub.4, 
RuCl.sub.2 P(C.sub.6 H.sub.5).sub.3 !.sub.3, RuH.sub.2 P(C.sub.6 
H.sub.5).sub.3 !.sub.4. RuHClP(C.sub.6 H.sub.5).sub.3 !.sub.4, 
RuH(HCOO)P(C.sub.6 H.sub.5).sub.3 !.sub.3, RuH(CH.sub.3 COO)P(C.sub.6 
H.sub.5).sub.3 !.sub.3, RUCl.sub.2 P(CH.sub.3)(C.sub.6 H.sub.5).sub.2 
!.sub.4, RuCl.sub.2 (C.sub.6 H.sub.5).sub.2 P(CH.sub.2).sub.2 P(C.sub.6 
H.sub.5).sub.2 !.sub.2, RuCl.sub.2 P(CH.sub.3).sub.3 !.sub.4, 
RuHClP(CH.sub.3).sub.3 !.sub.4, RuBr.sub.2 P(C.sub.6 H.sub.5).sub.3 
!.sub.4, and RuI.sub.2 P(C.sub.6 H.sub.5).sub.3 !.sub.4. It is needless 
to mention that complexes applicable are not limited to those enumerated 
above. 
The amount of the VIII-group transition metal complex for the method of 
production of an alcohol, varying with the reactor volume and economic 
merits, can be at a ratio within a range of from 1/100 to 1/100,000 in 
mole ratio, or more a range of from 1/100 to 1/100,000 in mole ratio, or 
more preferably, within a range of from 1/500 to 1/100,000 in mole ratio 
relative to the carbonyl compound which is the raction raw material. 
Bases applicable in the present invention include inorganic and organic 
bases. In the bases expressed by the general formula MY, for example, M is 
an alkali metal or an alkaline earth metal, and Y is a hydroxy group, 
alkoxy group, mercapto group or naphthyl group, and more specifically, 
applicable ones include KOH, KOCH3, KOCH(CH.sub.3).sub.2, KC.sub.10 
H.sub.8, KOC(CH.sub.3).sub.3, LiOH, LiOCH.sub.3, and 
LiOCH(CH.sub.3).sub.2, NaOH, NaOCH.sub.3, NaOCH(CH.sub.3).sub.2 as well as 
quaternary ammonium salt. 
The amount of the base as described above should be within a ragnge of from 
0.5 to 10,000 equivalents, or more preferably, from 2 to 40 equivalents 
relative to the VIII-group transition metal complex. 
As the nitrogen-containing organic compound used in the present invention, 
amine compounds are typical examples. 
The amine compound may be a mono-amino comprising of primary amine, 
secondary-amine, or tertiary amine expressed by a general fomrmula 
NR.sup.8 R.sup.9 R.sup.10, or a diamine expressed by a general formula 
R.sup.11 R.sup.12 N--Z--NR.sup.13 R.sup.14. 
In these formula, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13 
and R.sup.14 indicate hydrogen, or the same or different ones selected 
from alkyl group, cycloalkyl group and aryl group having a carbon number 
within a range of from 1 to 10, and may include cyclic diamine Z is a 
group selected from alkyl group, cycloalkyl group and aryl group having a 
carbon number of from 1 to 6. Examples include mono amine compounds such 
as methylamine, ethylamine, propylamine, butylamine, pentylamine, 
hexylamine, cyclopentylamine, cyclohexylamine, benzylamine, dimethlyamine, 
diethylamine, dipropylamine, dihexylamine, dicylopentylamine, 
dicyclohexylamine, dibenzylamine, diphenylamine, phenylethylamine, 
piperidino and piperadine; and diamine compounds such as methylenediamine, 
ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 
1,4-diaminobutane, 2,3-diaminobutane, 1,2-cyclopentanediamine, 
1,2-cyclohexanediamine, N-methylethylenediamine, 
N,N'-dimethylethylenediamine, N,N,N'-trimethylethylenediamine, 
N,N,N',N'-tetramethylethylenediamine, o-phenylenediamine, and 
p-phenylenediamine. 
The amount of these compounds should be within a range of from 1 to 1000 
equivalents relative to the transition metal complex in the case of 
monoamine compound, or more preferably, from 2 to 4 equivalents, and 
within a range of from 0.5 to 2.5 equivalents in the case of diamine 
compound, or more preferably, from 1 to 2 equivalents. 
The transition metal complex used as the catalyst, the base and the 
nitrogen-containing compound are indispensable for ensuring smooth 
progress of reaction. The absence of even any of these constituents makes 
it impossible to obtain a sufficient reaction activity. 
In the present invention, furthermore, any liquid solvent which can 
dissolve the raction raw materials and catalyst constituents may be used. 
Applicable solvents include aromatic hydrocarbon solvents such as toluene 
and xylene, aliphatic hydrocarbon solvents such as pentane and hexane, 
halogen-containing hydrocarbon solvents such as metylene chloride, ether 
type solvents such as ether and tetrahydrofuran, alcohol type solvents 
such as methanol, ethanol, 2-propanol, butanol, benzyl alcohol, and 
organic solvents containing heteroatoms such as acetonitrile, DMF and 
DMSO. Since the product is alcohol, alcohol type solvents are preferable. 
More preferably, 2-propanol may be preferably used. When the reaction 
substrate is hardly soluble in a solvent, a mixed solvent comprising ones 
selected from those enumerated above may be used. 
The amount of the solvent is determined from solubility of the reaction 
substrate and relative economic merits. In the case of 2-propanol, the 
reaction may be caused at a substrate concentration within a range of from 
a low concentration of under 1% to a state near the non-existence of 
solvent, but it is preferable to use it at a concentration within a range 
of from 20 to 50 wt %. 
In the present invention, the hydrogenation sufficiently proceeds under 1 
atm of hydrogen, because the catalyst has a very high activity. Taking 
account of economic merits, however, it should preferably be within a 
range of from 1 to 100 atm, or more preferably, from 3 to 50 atm. 
Considering economic merits for the process, it is possible to maintain a 
high activity even under a pressure of up to 10 atm. 
The reaction temperature should preferably be within a range of from 
15.degree. to 100.degree. C., while it is possible to cause the reaction 
at a temperature near the room temperature as within a range of from 
25.degree. to 40.degree. C . However, the present invention is 
characterized in that the raction proceeds even at a low temperature of 
from -100.degree. to 0.degree. C. The reaction is completed in a period of 
time within a range of from a few minutes to ten hours, depending upon 
such reaction conditions as reaction substrate concentration, temperature 
and pressure. 
The reaction system in the present invention may be in batch or continous. 
Now, the method of the present invention is described in further detail 
below by means of examples. 
In addition, the present invention relating to the method for producing an 
optically active alcohol provides also an embodiment wherein the 
above-mentioned asymmetric hydrogenation catalyst is a complex of a 
VIII-group metal, for example, a metal complex having an optically active 
ligand, one therein the base is a hydroxide or a salt of an alkali metal 
or an alkaline earth metal, or a quaternary ammonium salt, and one wherein 
the optically active compound as a nitrogen-containing asymmetric is a 
optically active amine compound. 
An asymmetric hydrogenation catalyst can be expressed, for example, by the 
following general formula (5): 
EQU M.sup.1 XmLn (5) 
(where, M' is a VIII-group transition metal such as ruthenium, rhodium, 
iridium, palladium, or platinum; X is hydrogen, a halogen atom, a carboxyl 
group, a hydroxy group, or a alkoxy group; L is an optically active 
phosphine ligand or an optically active organic arsenic ligand; and m and 
n are integers), and the base may be a metal salt or a quaternary ammonium 
salt expressed by the following general formula (6): 
EQU M.sup.2 Y (6) 
(where, M.sup.2 is an alkali metal or an alkaline earth metal; and Y is 
hydroxy group, alkoxy group, mercapto group or naphthyl group). 
The carbonyl compound which is the raw material in the present invention is 
expressed by the general formula (2) In this case, R.sup.3 is a 
non-substituted or substituted aromatic monocyclic or polycyclic 
hydrocarbon group, a saturated or unsaturated aliphatic or 
cyclic-hydrocarbon group, or a hetero-monocyclic or polycyclic group 
containing heteroatoms such as nitrogen, oxygen or sulfur atoms, and 
applicable ones include, for example, aromatic monocyclic or polycyclic 
groups such as phenyl group, 2-methylphenyl, 2-ethylphenyl, 
2-isopropylphenyl, 2-tert-butylphenyl, 2-methoxyphenyl, 2-chlorophenyl, 
2-vinylphenyl, 3-methylphenyl, 3-ethylphenyl, 3-isopropylphenyl, 
3-methoxyphenyl, 3-chlorophenyl, 3-vinylphenyl, 4-methylphenyl, 
4-ethylphenyl, 4-isopropylphenyl, 4-tert-butylphenyl, 4-vinylphenyl, 
cumenyl, mesityl, xylyl, 1-naphthyl, 2-naphthyl, anthryl, phenanthryl, and 
indenyl; and hetero-monocyclic or polycyclic groups and ferrocenyl group 
such as thienyl, furyl, pyranyl, xanthenyl, pyridyl, imidazolyl, indolyl, 
carbazolyl, and phenanthrolyl. R.sup.4 is hydrogen, saturated or 
un-saturated hydrocarbon group, aryl group, or a functional group 
containing heteroatoms, and applicable ones include, for example, alkyl 
groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl; 
cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl and 
cyclohexyl; and unsaturated hydrocarbon and other groups such as benzyl, 
vinyl and allyl. Furthermore, .beta.-keto acid derivatives having a 
functional group at .beta.-position are also applicable. 
In case of cyclic group formed by conecting R.sup.3 and R.sup.4, for 
example, saturated or unsaturated cyclo-aliphatic groups providing cyclic 
ketone such as cyclopentanone, cyclohexanone, cycloheptanone, 
cyclopentenone, cyclohexenone, cycloheptenone; substituted saturated or 
unsaturated cyclo-aliphatic groups having substitution groups selected 
from alkyl, aryl, unsaturated alkyl, aliphatic or cyclo-aliphatic group 
containing hetero atom; are mentioned. 
In the transition metal complex expressed by the general formula (5) in the 
present invention, M.sup.1 is a VIII-group transition metal such as 
ruthenium, rhodium, iridium, palladium and platinum, and among others, 
ruthenium is particularly preferable. X is hydrogen, halogen atom, 
carboxyl group, hydroxyl group or alkoxy group. L is an optically active 
phosphine ligand or the like, and applicable ones include 
BINAP:2,2'-bis-(diphenylphosphino)-1,1'-binaphthyl, BINAP derivative 
having alkyl group or aryl group connected to naphthyl ring, such as 
H.sub.8 BINAP; BINAP derivative having 1-5 alkyl substitution group(s) at 
sito of aromatic ring on phosphorus atom, for example TolBINAP: 
2,2'-bis-(di-p-tolylphosphino)-1,1'-binaphthyl, BICHEP: 
2,2'-bis-(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl, BPPFA; 
1-1,2-bis(diphenylphosphino)ferrocenyl! ethyldimethylamine, CHIRAPHOS; 
2,3-bis(diphenylphosphino) butane, CYCPHOS: 
1-cyclohexyl-1,2-bis(diphenylphosphino)ethane, DEGPHOS: 
substitution-3,4-bis(diphenylphosphino)pyrmethylolidine, DIOP: 
2,3-0-isopropylidene-2,3-dihydroxy-1,4-bis(diphenyl-phosphino)butane, 
DIPAMP: 1,2-bis(0-methoxy phenyl)phenylphosphino!ethane, DuPHOS: 
substitued-1,2-bis(phospholano) benzene, NORPHOS: 
5,6-bis(diphenylphosphino)-2-norbornene, PNNP: 
N,N'-bis(diphenylphosphino)-N,N'-bis(1-phenylethyl) ethylenediamine, 
PROPHOS 1,2-bis(diphenylphosphino)propane, and SKEWPHOS: 
2,4-bis(diphenylphosphino)pentane. In addition, an optcally active 
phosphine ligand (an optically active phosphine ligand comprising 
substitution group having different group, or an optically active 
phosphine ligand of which at least one group is an optically active group) 
may be used. A bidentate phosphine ligand has an n of 1 or 2, and a 
monodentate phosphine ligand has an n of 3 or 4. It is needless to mention 
that the optically active phosphine ligand applicable in the present 
invention is not limited at all to these values, and the metal is not 
limited at all to ruthenium. 
The amount of the VIII-group transition metal complex in the present 
invention, varying with the reactor, the reaction system and economic 
merits, can be at a ratio within a range of from 1/100 to 1/100,000 in 
mole ratio, or more preferably, within a range of from 1/600 to 1/10,000 
in mole ratio relative to the carbonyl compound which is the reaction 
substrate. 
In the base expressed by the general formula M.sup.2 Y used in the present 
invention, M.sup.2 is an alkali metal or an alkaline earth metal, and Y is 
hydroxy group, alkoxy group, mercapto group or naphthyl group, and more 
specifically, applicable ones include KOH, KOCH.sub.3, 
KOCH(CH.sub.3).sub.2, KOC(CH.sub.3).sub.3, KC.sub.10 H.sub.8, LiOH, 
LiOH.sub.3, and LiOCH(CR.sub.3).sub.2, NaOH, NaOCH.sub.3, 
NaOCH(CH.sub.3).sub.2, NaOC(CH.sub.3).sub.3 as well as quaternary ammonium 
salt. 
The consumption of the base as described above should be within a range of 
from 0.5 to 100 equivalents, or more preferably, from 2 to 40 equivalents 
relative to the VIII-group transition metal complex. 
The nitrogen-containing compound such as an optical active amino compound 
used in the present invention may be an opically atctive monoamine in 
which at least one of the substitution groups is an optically active group 
and the remaining ones include hydrogen, or saturated or unsaturated 
hydrocarbon group or aryl group, or an optically active diamine compound 
expressed by the following general formula (7): 
##STR4## 
(where, R.sup.15, R.sup.16, R.sup.17 and R.sup.18 are hydrogen or 
saturated or unsaturated hydrocarbon group, aryl group, urethane group or 
sulfonyl group, and R.sup.19, R.sup.20, R.sup.21 and R.sup.22 are the same 
or different groups such that carbons bonded with these substitution 
groups form centers of asymmetricity, and represent hydrogen or alkyl 
group, aromatic monocyclic or polycyclic, saturated or unsaturated 
hydrocarbon group, and cyclic hydrocarbon group). Examples include such 
optically active diamine compounds as optically active 
1,2-diphenylethylene diamine, 1,2-cyclohexanediamine, 
1,2-cycloheptanediamine, 2,3- dimethylbutanediamine, 1-methyl-2,2-diphenyl 
ethylenediamine, 1-isobutyl-2,2-diphenylethylenediamine, 
1-isopropyl-2,2-diphenylethylenediamine, 
1-methyl-2,2-di(p-methoxyphenyl)ethylenediamine, 
1-isobutyl-2,2-di(p-methoxyphenyl)ethylenediamine, 
1-isopropyl-2,2-di(p-methoxyphenyl)ethylenediamine) 
1-benzyl-2,2-di(p-methoxyphenyl)ethylenediamine, 
1-methyl-2,2-dinaphthylethylenediamine, 
1-isobutyl-2,2-dinaphthylethylenediamine, and 
1-isopropyl-2,2-dinaphthyl-ethylenediamine, and optically active diamine, 
compounds in which one or both of the substitution groups R.sup.15 and 
R.sup.17 are sulfonyl group or urethane group. Optically active diamine 
compounds are not limited to the optically active ethylene-diamine 
derivatives enumerated above, but include also optically active 
propanediamine, butanediamine and phenylenediamine derivatives. The amount 
of these optically active amine compounds should be within a range of from 
1 to 10 equivalents relative to the transition metal complex in the case 
of a monoamine compound, or more preferably, from 2 to 4 equivalents, and 
within a range of from 0.6 to 2.5 equivalents in the case of a diamine 
compound, or more preferably, from 1 to 2 equivalents. 
In the present invention, it is important, in order to obtain a high 
optical yield, to achieve an appropriate combination of an absolute 
configuration of the optically active ligand and the absolute 
configuration of the optical active nitrogen-containing compound in the 
asymmetric hydrogenation catalyst as the catalyst component. The 
combination of S-phosphine ligand and S,S-diamine is, for example, best 
choice and gives (R)-- alcohol. The combination of S-phosphine ligand and 
R,R-diamine, while the reaction proceeds, results in an extremely low 
optical yield. 
The optical active transition metal complex, the base and the optical 
active nitrogen-containing compound used as catalyst component in the 
present invention as described above are indispensable for achieving a 
high optical yield. Lack of even any of these constituents makes it 
impossible to obtain alcohol with a sufficient optical activity and a high 
purity. 
In the present invention, furthermore, any liquid solvent which can 
dissolve the reaction raw materials and catalyst components may be used. 
Applicable solvents include aromatic hydrocarbon solvents such as toluene 
and xylene, aliphatic hydrocarbon solvents such as pentane and hexane, 
halogen-containing hydrocarbon solvents such as methylene chloride, 
diethyl ether type solvents such as ether and tetrahydrofuran, alcohol 
type solvents such as methanol, ethanol, 2-propanol, butanol, benzyl 
alcohol, and organic solvents containing heteroatoms such as acetonitrile, 
DMF and DMSO. Since the product is alcohol, alcohol type solvents are 
preferable. More preferably, 2-propanol may be preferably used. When the 
reaction substrate is hardly soluble in a solvent, a mixed solvent 
comprising ones selected from those enumerated above may be used. 
The amount of solvent is determined from solubility of the reaction 
substrate and relative economic merits. In the case of 2-propanol, the 
reaction may be caused at a substrate concentration within a range of from 
a low concentration of under 1% to a state near the non-existence of 
solvent, but it is preferable to use it at a concentration within a range 
of from 20 to 50 wt. % 
In the present invention, the hydrogenation sufficiently proceeds under 1 
atm of hydrogen because the catalyst has a very high activity. Taking 
account of economic merits, however, it should preferably be within a 
range of from 1 to 100 atm, or more preferably, from 3 to 50 atm. 
Considering economic merits for the process as a whole, it is possible to 
maintain a high activity even under a pressure of up to 10 atm. 
The reaction temperature should preferably be within a range of from 
15.degree. to 100.degree. C., while it is possible to cause the reaction 
at a temperature near the room temperature as within a range of from 
25.degree. to 40.degree. C. However, the present invention is 
characterized in that the reaction proceeds even at a low temperature of 
from -100.degree. to 0.degree. C. The reaction is completed in a period of 
time within a range of from a few minutes to ten hours, depending upon 
such reaction conditions as reaction substrate concentration, temperature 
and pressure. Now, the present invention is described in detail by means 
of examples. 
The form of reaction in the present invention may be in batch or continuous 
.