Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
1999-03-22
2001-11-06
Solola, T. A. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C549S221000, C549S435000, C502S164000, C502S230000, C502S326000
Reexamination Certificate
active
06313317
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel ruthenium-phosphine complex represented by the following general formula (1) and to an asymmetric hydrogenation catalyst comprising the complex.
[{RuX(L)}
2
(&mgr;-X)
3
]
−
[R
2
2
NH
2
]
+
(1)
2. Description of Prior Art
Many organic synthetic reactions using a transition metal complex as the catalyst have been developed and exploited to achieve various objects. In particular, there have been many reports concerning asymmetric catalysts used in an asymmetric hydrogenation reaction. There have been many studies in which complexes comprising a transition metal atom and an optically active phosphine are used as an asymmetric hydrogenation catalyst since a report was made that a complex containing, as the ligands, a rhodium atom and an optically active phosphine was selectively used as an asymmetric hydrogenation catalyst to prepare an optically active compound with high enantiomer excess.
For example, in J. Chem. Soc., Chem. Commun. (1985), 922 and J. Chem. Soc., Perkin Trans. I, (1987), 1571, technologies are disclosed in which an acylaminoacrylic acid derivative is hydrogenated using 2,2′-bis(diphenylphosphine)-1,1′-binaphthyl-ruthenium complex (Ru
2
Cl
4
(BINAP)
2
·Et
3
N, which is hereinafter called “BINAP-Ru complex”) to produce an optically active amino acid derivative.
Recently, a ruthenium complex of p-MeO-BINAP, namely, [{RuCl(p-MeO-BINAP)}
2
(&mgr;-Cl)
3
]
−
[Et
2
NH
2
]
+
has been disclosed in Organometallics, 15 (1996), 1521. Moreover, Japanese Patent Application No. 8-359818 discloses an asymmetric hydrogenation reaction of ketones by using ((5,6), (5′, 6′)-bis (methylenedioxy)biphenyl-2,2′-diyl)bis(diphenylphosphine)-ruthenium complex (hereinafter called “SEGPHOS-Ru complex”).
However, the ruthenium complexes used in Japanese Patent Application No. 8-359818, for example, are complicated in the preparation of the complexes, have a problem in stability and yield and production of complicated mixtures. These complexes also have insufficient catalytic activity and durability.
Ruthenium metals are relatively inexpensive among transition metals and are expected to serve as an industrially advantageous catalyst. These catalysts, however, have unsolved problems in the preciseness and application of reaction. Hence there is a demand for catalysts which can be easily produced, are inexpensive, have a high activity and durability, and can give a enantiomer excess in an asymmetric reaction, making products of optically high purity.
SUMMARY OF THE INVENTION
The inventors of the present invention have conducted earnest studies in response to such a demand, and, as a result, have found a novel ruthenium complex which can be used as a common synthetic catalyst when an optically inactive material is used as the ligand in the complex and in turn as an asymmetric synthetic catalyst when an optically active material is used as the ligand and which has high catalytic activity, the objective complex being obtained in a high yield in a simple operation. The present invention has thus been completed.
1. Thus the present invention provides a ruthenium-phosphine complex represented by the general formula (1):
[{RuX(L)}
2
(&mgr;-X)
3
]
−
[R
2
2
NH
2
]
+
(1)
wherein R
2
represents a hydrogen atom, an alkyl group having 1-4 carbon atoms, a cycloalkyl group having 3-8 carbon atoms, a phenyl group or a benzyl group and L represents a diphosphine ligand represented by the general formula (2):
wherein R
1
represents a phenyl group which is optionally substituted with up to three substituents selected from alkyl of 1-4 carbon atoms, alkoxy of 1-4 carbon atoms, methylenedioxy, halogen, halomethyl, cycloalkyl of 3-8 carbon atoms, 1-naphthyl and 2-naphthyl, and X represents a halogen atom.
2. The present invention further provides a method for preparing a ruthenium-phosphine complex, said method comprising reacting a ruthenium complex represented by the general formula (3):
[RuX(arene)(L)]X (3)
wherein X represents a halogen atom, arene represents a phenyl group which is optionally substituted with up to six substituents selected from alkyl of 1-3 carbon atoms, alkoxycarbonyl of 1-2 carbon atoms and halogen and L represents a tertiary diphosphine ligand represented by the general formula (2):
wherein R
1
represents a phenyl group which is optionally substituted with up to three substituents selected from alkyl of 1-4 carbon atoms, alkoxy of 1-4 carbon atoms, methylenedioxy, halogen, trihalomethyl, cycloalkyl of 3-8 carbon atoms, 1-naphthyl and 2-naphthyl, with an ammonium salt represented by the general formula (4)
R
2
2
NH.HX (4)
wherein R
2
represents a hydrogen atom, an alkyl group having 1-4 carbon atoms, a cycloalkyl group having 3-8 carbon atoms, a phenyl group or a benzyl group and X represents a halogen atom, to produce a ruthenium-phosphine complex represented by the general formula (1):
[{RuX(L)}
2
(&mgr;-X)
3
]
−
[R
2
2
NH
2
]
+
(1)
wherein R
2
, L and X are the same as defined above.
3. The present invention further provides a method for preparing a ruthenium-phosphine complex, said method comprising reacting a ruthenium complex represented by the general formula (5):
[RuX
2
(arene)]
2
(5)
wherein X represents a halogen atom and arene represents a phenyl group which is optionally substituted with up to six substituents selected from alkyl of 1-3 carbon atoms, alkoxycarbonyl of 1-2 carbon atoms and halogen, with a tertiary diphosphine ligand represented by the general formula (2):
wherein R
1
represents a phenyl group which is optionally substituted with up to three substituents selected from alkyl of 1-4 carbon atoms, alkoxy of 1-4 carbon atoms, methylenedioxy, halogen, trihalomethyl, cycloalkyl of 3-8 carbon atoms, 1-naphthyl and 2-naphthyl, and an ammonium salt represented by the general formula (4):
R
2
2
NH.HX (4)
wherein R
2
represents a hydrogen atom, an alkyl group having 1-4 carbon atoms, a cycloalkyl group having 3-8 carbon atoms, a phenyl group or a benzyl group and X represents a halogen atom, to produce a ruthenium-phosphine complex represented by the general formula (1):
[{RuX(L)}
2
(&mgr;-X)
3
]
−
[R
2
2
NH
2
]
+
(1)
4. According to the present invention, there is also provided an asymmetric hydrogenation catalyst comprising the aforementioned ruthenium-phosphine complex, the catalyst being used to produce allyl alcohols, olefin acids or ketones.
DETAILED DESCRIPTION OF THE INVENTION
The invention will be explained in detail.
The novel ruthenium-phosphine complex of the present invention is, as aforementioned, a compound represented by the general formula (1):
[{RuX(L)}
2
(&mgr;-X)
3
]
−
[R
2
2
NH
2
]
+
(1)
Specific examples of the tertiary diphosphine represented by L in the above general formula (1) include (5,6), (5′, 6′)-bis (methylenedioxy)biphenyl-2,2′-diyl-bis(diphenylphosphine) (hereinafter abbreviated as “SEGPHOS”) containing a phenyl group as R
1
in the general formula (2):
and phosphine compounds containing as R
1
, a 4-methylphenyl group, 4-tert-butylphenyl group, 3-methylphenyl group, 3,5-dimethylphenyl group, 3,5-ditert-butylphenyl group, 4-chlorophenyl group, 4-fluorophenyl group, 4-trifluoromethylphenyl group, 4-methoxyphenyl group, 3,5-dimethoxyphenyl group, 3,4-methylenedioxyphenyl group, 3,5-dimethyl-4-methoxyphenyl group, 3,5-ditert-butyl-4-methoxyphenyl group, 2-naphthyl group, 1-naphthyl group, cyclohexyl group or cyclopentyl group. Preferred examples are phosphine compounds containing a phenyl group, 4-methylphenyl group, 4-tert-butylphenyl group, 3,5-dimethylphenyl group, 3,5-dimethyl-4-methoxyphenyl group, 3,5-ditert-butylphen
Saito Takao
Sayo Noboru
Yokozawa Tohru
Kubovcik & Kubovcik
Solola T. A.
Takasago International Corporation
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