Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-06-27
2001-06-19
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C549S218000, C568S010000, C568S017000, C585S400000
Reexamination Certificate
active
06248848
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a phosphine derivative, a polymer having structural units derived from the same as a polymer-forming base monomer, and complexes of these with a transition metal such as rhodium. This invention further relates to a method for obtaining an optically active compound in the presence of these transition metal complexes, which are utilizable as useful catalysts in asymmetric hydroformylation reactions.
BACKGROUND OF THE INVENTION
Many transition metal complexes have hitherto been used as catalysts for organic synthesis reactions. In particular, noble-metal complexes are extensively utilized, despite their expensiveness, since they are stable and easy to handle. Many investigations were made on syntheses using transition metal complexes including such noble-metal complexes as catalysts. As a result, many reports have been made on techniques making it possible to carry out organic synthesis reactions, including asymmetric reactions, which have been regarded as impossible with any conventional technique.
There are various types of optically active ligands for use in such asymmetric-synthesis catalysts. Among the ligands for use in asymmetric hydroformylation reactions using transition metal-phosphine complexes, one of the ligands having the highest degree of chiral recognition is 2-diphenylphosphino-1,1′-binaphthalen-2′-yloxy(1,1′-binaphthalene-2,2′-diyloxy)phosphine (hereinafter referred to simply as “BINAPHOS”). There are reports on the use of a rhodium complex containing BINAPHOS as a ligand in an olefin hydroformylation reaction, which is a reaction for forming asymmetric carbon-carbon bonds (see JP-A-6-263776 and JP-A-6-316560). (The term “JP-A” as used herein means an “unexamined published Japanese patent application”.)
However, such expensive catalysts are unable to be recovered, or can be recovered only by a complicated separation method which is always accompanied by an undesirable loss. Furthermore, reuse of the recovered homogeneous catalysts is impossible and/or uneconomical. There has hence been a desire for a catalyst which can be easily recovered and reused and is capable of fully retaining its activity and, in particular, selectivity during repeated use.
With respect to synthetic chiral polymers, the application thereof to racemate separation media, reagents for asymmetric syntheses, catalysts, and the like is being extensively investigated. Rapid progress is being made recently in investigations on asymmetry recognition among the various functions of these chiral polymers. In particular, in the application thereof to stereoselective organic reactions, the chiral polymers can be used in a method different from those for general homogenous reaction systems because a specific reaction field constituted of the polymers is used.
Use of a polymeric reagent or polymeric catalyst in organic syntheses has an advantage that industrial processes can be improved because the reaction products can be easily separated and the reagent or catalyst can be reused.
For example, a report has been made on a process comprising reacting an optically active amino acid with 4-vinylbenzenesulfonyl chloride to obtain a chiral monomer, polymerizing the monomer with styrene and divinylbenzene to obtain a chiral polymer,
reacting this polymeric ligand with diborane to obtain a polymer-supported chiral oxaborolidinone, and using this compound as a Lewis acid catalyst to conduct the Diels-Alder reaction of cyclopentadiene with methacrolein (see S. Itsuno et al.,
Tetrahedron: Asymmetry,
1995, Vol. 6, p. 2547).
There also is a report on a method in which a Mn(II)-salen complex is polymerized
and the resultant polymer is used to conduct the asymmetric epoxidation reaction of an olefin (see S. Sivaram et al.,
Tetrahedron: Asymmetry,
1995, Vol. 6, p. 2105).
Furthermore, there is a report on a method which comprises copolymerizing optically active 2-p-styryl-4,5-bis[(dibenzophosphoryl)methyl)-1,3-dioxolane with styrene to obtain a chiral polymer,
coordinating platinum chloride to this polymeric ligand, and using the resultant coordination compound to conduct the hydroformylation reaction of styrene in the presence of tin chloride (see J. K. Stille et al.,
J. Org. Chem.,
1986, Vol. 51, p. 4189).
However, all the prior art techniques have insufficient catalytic activity or result in an enantiomer excess lower than those in the case of reacting monomers. None of those prior art techniques has been put to industrial use.
SUMMARY OF THE INVENTION
As described above, there has been a desire for a polymer-supported ligand which, when used as a catalyst for asymmetric synthesis reactions, gives satisfactory results concerning catalytic activity, enantiomer excess, etc. An object of the present invention is to meet these requirements.
The present inventors have found that a polymeric ligand obtained by synthesizing a monomer which comprises a biphenyl framework having a diarylphosphino group at the 2′-position and a phosphite at the 2-position and in which the phosphite moiety has a naphthyl framework having two vinyl groups respectively at the 6- and 6′-positions, and then copolymerizing the monomer with a styrene derivative and a divinylbenzene derivative is an excellent ligand for use in asymmetric catalytic reactions. The present invention has been completed based on this finding.
The present invention provides a 2′-diarylphosphino-1,1′-biphenylen-2-yloxy(6,6′-divinyl-1,1′-binaphthalene-2,2′-diyloxy)phosphine derivative represented by the following general formula (I):
wherein Ar is an optionally substituted phenyl group or an optionally substituted naphthyl group; R
1
and R
2
each independently is a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a halogen-substituted lower alkyl group, or a benzyloxy group; and R
3
is a lower alkyl group, a lower alkoxy group, a halogen atom, a halogen-substituted lower alkyl group, or a benzyloxy group; provided that R
2
and R
3
may be bonded to each other to form a hydrocarbon ring, which may have one or more substituents selected from lower alkyl groups, halogen atoms, lower alkoxy groups, halogenated lower alkyl groups, a benzyloxy group, and a vinyl group.
The present invention further provides an oligomer or polymer having structural units derived from a 2′-diarylphosphino-1,1′-biphenylen-2-yloxy(6,6′-divinyl-1,1′-binaphthalene-2,2′-diyloxy)phosphine derivative which are represented by the following general formula (III):
wherein R
1
, R
2
, R
3
, and Ar have the same meanings as defined above; and k is an integer of 2 to 100.
The present invention furthermore provides transition metal complexes obtained by causing a transition metal compound to act on the compound represented by general formula (I) and on the polymer represented by general formula (III), respectively.
Another object of the present invention is to provide a process for producing an optically active &agr;-methylaldehyde compound represented by the following general formula (B):
wherein R
5
is an alkyl group having 1 to 8 carbon atoms, an optionally substituted phenyl group, a naphthyl group, or an acetoxy group,
which comprises subjecting an olefin compound represented by the following general formula (A):
wherein R
5
has the same meaning as defined above, to asymmetric hydroformylation in the presence of any of the transition metal complexes.
DETAILED DESCRIPTION OF THE INVENTION
In compound (I) of the present invention, Ar is an optionally substituted phenyl group or an optionally substituted naphthyl group. Examples of the substituents thereof include lower alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, and isobutyl, halogen atoms such as fluorine, chlorine, and bromine, lower alkoxy groups having 1 to 4 carbon atoms, such as methoxy, ethoxy, propoxy, and butoxy, halogenated lower alkyl groups such as trifluoromethyl and trichloromethyl, and benzyl
Itoi Yohei
Tamao Kyoko
Sughrue Mion Zinn Macpeak & Seas, PLLC
Takasago International Corporation
Wu David W.
Zalukaeva Tanya
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