Organic compounds -- part of the class 532-570 series – Organic compounds – Phosphorus containing
Reexamination Certificate
2002-12-30
2004-04-06
Vollano, Jean F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Phosphorus containing
C502S162000, C556S013000
Reexamination Certificate
active
06717016
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel optically active phosphine compound, a transition metal complex including the same phosphine compound as a ligand and a transition metal catalyst useful for a variety of asymmetric synthetic reactions.
2. Description of the Related Art
There have hitherto been many reports on transition metal complexes which can be utilized for asymmetric syntheses such as asymmetric hydrogenations, asymmetric isomerizations, asymmetric hydrosilylations, asymmetric Heck reactions, asymmetric hydroborations and the like. Inter alia, complexes in which transition metal complexes such as ruthenium, rhodium, iridium, palladium and the like are coordinated with an optically active phosphine compound are potent catalysts for asymmetric reactions and some of the catalysts have been used for industrialization. (Asymmetric Catalysis in Organic Synthesis, Ed., R. Noyori, Wiley & Sons, New York (1994)). One of these ligands is a phospholane type compound. The phospholane compound when used as a ligand for a transition metal is useful for asymmetric syntheses such as asymmetric hydrogenations. (Document (A) WO91/17998, document (B) WO93/01199).
However, the phospholane type ligands described in documents (A) and (B) have an optically active phospholane ring structure, and a preparation of the phospholane ring needs expensive optically active 1,4-diols. The preparation of said 1,4-diols requires a special process and equipment (e.g., an electrochemical reaction such as a “Kolbe Reaction”), which makes industrialization difficult. Additionally, selectivities (diastereoselectivity, enantioselectivity) and catalytic activities of said phospholane ligands are not sufficient depending upon the reaction and reaction substrate and, thus, an improvement in a catalyst is occasionally demanded.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a novel phosphine compound having excellent performance (diastereoselectivity, enantioselectivity, catalytic activity) as a ligand of catalysts for asymmetric reactions, in particular, asymmetric hydrogenation reactions. Furthermore, an object of the present invention is to provide an inexpensive preparation of the novel phosphine compound.
In order to achieve the above objects, the present inventors made extensive studies. As a result, it was found that a transition metal complex coordinated with a novel phosphine compound having a fused ring of a benzene ring and a phospholane ring is effective in an asymmetric hydrogenation reaction. It has also been found that this transition metal complex has excellent catalytic activity and enantioselectivity. The invention has been completed based on this finding.
PREFERRED EMBODIMENTS OF THE INVENTION
The present invention will be described in detail below.
One of the phosphine compounds of the present invention is represented by the following general formula (1):
where R
1
is a linear or branched alkyl group having 1 to 5 carbon atoms, R
2
and R
3
represent independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R
4
, R
5
, R
6
and R
7
represent independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a dialkylamino group where the alkyl has 1 to 5 carbon atoms, and X represents a functional group that forms a stable bond with a phosphorous atom, with the proviso that R
4
and R
5
or R
5
and R
6
or R
6
and R
7
taken together with the carbon atoms to which they are attached optionally form a ring or fused ring.
R
1
mentioned above includes a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, or neopentyl group.
As R
2
and R
3
, groups such as a methyl group, ethyl group, n-propyl group, and isopropyl group are mentioned.
Examples of R
4
, R
5
, R
6
, R
7
include a halogen atom such as fluorine, chlorine, bromine, and iodine; an alkyl group having 1 to 5 carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, and neopentyl group; an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group, ethoxy group, n-propoxy group, isopropoxy group, and tert-butoxy group; and a dialkylamino group where the alkyl has 1 to 5 carbon atoms, such as dimethylamino group, diethylamino group, pyrrolidino'group, and piperidino group.
Furthermore, the above-described ring or fused ring is a five to ten membered saturated or unsaturated ring such as a benzene ring, cyclopentene ring, cyclohexene ring, cyclopentadiene ring, indene ring, naphthalene ring, or heterocyclic ring such as a methylenedioxy ring system, ethylenedioxy ring system, or trimethylenedioxy ring system.
Specific examples of X are an alkyl group having 1 to 36 carbon atoms which may have a substituent, an aralkyl group, an aryl group which may have a substituent, a heterocyclic group, an alkoxy group, and an amino group. The substituent can be an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a haloalkyl group having 1 to 5 carbon atoms, a halogen atom, an amino group, a mono alkylamino group and a dialkylamino group. Further, the alkyl group having 1 to 5 carbon atoms and alkoxy group having 1 to 5 carbon atoms can be any of those as described above.
Preferred specific examples of X are phenyl groups which may have a substituent, such as a phenyl group, 3-methoxyphenyl group, 3,4-methylenedioxyphenyl group, 1-naphthyl group, 2-naphthyl group, 3,5-di(tert-butyl)-4-methoxyphenyl group, 2-(diphenylphosphino) phenyl group, 2-(di(4-tolyl)phosphino)phenyl group, 2-(di(3,5-xylyl)phosphino)phenyl group, 2-(bis(3,5-di(tert-butyl)-4-methoxyphenyl)phosphino)phenyl group, 2-(di(1-naphthyl)phosphino)phenyl group, 2-(di(2-naphthyl)phosphino)phenyl group, 6-methoxy-2-(diphenylphosphino)phenyl group, and 5,6-methylenedioxy-2-(diphenylphosphino)phenyl group.
Another compound of the present invention is represented by the following general formula (2):
where R
1
-R
7
are as defined above, R
11
is a linear or branched alkyl group having 1 to 5 carbon atoms, R
21
and R
31
represent independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R
41
, R
51
, R
61
and R
71
represent independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a dialkylamino group where the alkyl has 1 to 5 carbon atoms, and Y represents a functional group that forms a stable bond with phosphorous with the proviso that R
41
and R
51
or R
51
and R
61
or R
61
and R
71
taken together with the carbon atoms to which they are attached optionally form a ring or a fused ring.
R
11
mentioned above includes a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, and neopentyl group.
As R
21
and R
31
, groups such as a methyl group, ethyl group, n-propyl group, isopropyl group are mentioned.
Examples of R
41
, R
51
, R
61
, R
71
include a halogen atom, such as fluorine, chlorine, bromine, and iodine; an alkyl group having 1 to 5 carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, and neopentyl group; an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group, ethoxy group, n-propoxy group, isopropoxy group, and tert-butoxy group; a dialkylamino group where the alkyl has 1 to 5 carbon atoms, such as a dimethylamino group, diethylamino group, pyrrolidino group, and piperidino group.
Furthermore, the above-described ring or fused ring is a five to ten membered saturated or unsaturated ring represented by a benzene ring, cyclopentene ring, cyclohexene ring, cyclopentadiene ring, indene
Saito Takao
Shimizu Hideo
Kubovcik & Kubovcik
Takasago International Corporation
Vollano Jean F.
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