Transition-Metal-Catalyzed Asymmetric Organic Synthesis via Polymer-Attached Optically Active Phosphine Ligands. 13. Asymmetric Hydrogenation with Polymer Catalysts Containing Primary and Chiral Secondary Pendant Alcohols

Article abstract of DOI:10.1021/jo00213a020

The copolymerizations of (4S,5S)-2-p-styryl-4,5-bis<(diphenylphosphino)methyl>-1,3-dioxolane <(S,S)-5> with a cross-linking monomer, ethylene 1,2-dimethacrylate (7), and methacrylates bearing both a primary alcohol function and a chiral secondary alcohol function, (2S)-, (2RS)-, or (2R)-2,3-dihydroxypropyl methacrylate <(S)-2, (RS)-2, and (R)-2, respectively>, gave polymers (6a-c, respectively) onto which rhodium was exchanged via the chloro(1,5-cyclooctadiene)rhodium(I) dimer.The resulting insoluble polymers containing chiral rhodium centers and the ancillary alcohol sites catalyzed the hydrogenation of olefins in ethanol to yield chiral N-acylamino acids and hydratropic acid.The catalyst containing the R alcohol (6a) gave amino acids in an optical yield that was 6percent higher than that obtained from polymer (6b) bearing the racemic alcohol and 8percent higher than that obtained from catalyst with the S alcohol when the reactions were performed in THF.