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Author PARRINELLO, GIOVANNI
Title ASYMMETRIC HYDROFORMYLATION CATALYZED BY HOMOGENEOUS AND POLYMER-SUPPORTED CHIRAL PLATINUM COMPLEXES
Descript 194 p
Note Source: Dissertation Abstracts International, Volume: 47-11, Section: B, page: 4527
Thesis (Ph.D.)--Colorado State University, 1986
A complex of Pt(II) containing the chiral ligand, N-(t-butoxy-carbonyl) - (2S,4S)-4-(diphenylphosphino)-2- (diphenylphosphino)-methyl pyrrolidine, (-)BPPM , was used in the presence of stannous chloride to catalyze the hydroformylation of a variety of prochiral olefins. Although the branched/normal (b/n) ratios were low ((TURN)0.5), high ee's were achieved in the hydroformylation of styrene (70-80%), vinyl acetate (82%), N-vinylphthalimide (73%), methyl methacrylate (60%), norbornene (60%), p-isobutylstyrene (80%), 2-vinylnaphtha- lene (77%), 2-ethenyl-6-methoxynaphthalene (81%), 4-(2-thienyl- carbonyl)styrene (78%), and 4,4,6-trimethyl-2-vinyl-1,3,2-dioxoborinane (60% de)
The monomer N-acryloyl-(2S,4S)-4-(diphenylphosphino)-2- (diphenylphosphino)methyl pyrrolidine, which was prepared from (-)BPPM, was copolymerized with either hydroxyethyl methacrylate/ ethylene dimethacrylate or styrene/divinylbenzene. Platinum chlo- ride was exchanged onto these polymers and the polymer-supported catalysts obtained were used in the hydroformylation of styrene to give the ee achieved with the homogeneous (-)BPPM PtCl(,2)/SnCl(,2) catalyst. When the hydroformylation of styrene, 2-ethenyl-6-meth- oxynaphthalene, and vinyl acetate with (-)BPPM PtCl(,2)/SnCl(,2) was carried out in the presence of triethyl orthoformate, enantiomerically pure acetals were obtained
An optically active ligand, analogous to 2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(dibenzophosphole)butane (DBP-DIOP) attached to linear and to cross-linked polymer supports was obtained by copoly- merization of (4R,5R)-2-(p-styryl)-4,5-bis (dibenzophosphole)methyl -1,3-dioxolane with styrene or styrene and divinylbenzene. Exchange of Pt(II) onto these polymers followed by addition of stannous chlo- ride gave polymer-supported catalysts which were used for the asymmetric hydroformylation of a variety of olefins. Relatively high ee's were obtained in the hydroformylation of styrene (56-65%), vinyl acetate (56-61%), and N-vinylphthalimide (58-70%)
A platinum complex containing N-(t-butoxycarbonyl)-(2S,4S)-4-(dibenzophosphole)-2- (dibenzophosphole)methyl pyrrolidine, (+) BBBM , was used in the hydroformylation of styrene. The reaction gave a b/n ratio of 1.5, but the highest ee achieved was only 52%
Hydrocarboalkoxylation of styrene with Pd(II) complexes containing the chiral ligands AMPHOS or (S)-(R)-PPFA provided the branched ester regiospecifically, but low ee's were achieved (9.3-19.4%)
School code: 0053
DDC
Host Item Dissertation Abstracts International 47-11B
Subject Chemistry, Organic
0490
Alt Author Colorado State University
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