RHODIUM- AND PLATINUM-CATALYZED ASYMMETRIC HYDROFORMYLATION WITH (2S,3R)-2,3-BIS(DIPHENYLPHOSPHINO)BUTANE AS THE CHIRAL LIGAND

Article abstract of DOI:10.1016/0022-328X(85)87017-0

Some mono- and disubstituted ethenes have been asymmetrically hydroformylated with rhodium and platinum catalysts using (2S,3S)-2,3-bis(diphenylphosphino)butane (Chiraphos) as the chiral ligand (maximum optical yield ca 45percent).The results are compared with those obtained when the chiral ligand is (4R,5R)-2,2-dimethyl-4,5-bis(diphenylphosphinomethyl)-1,3-dioxolane (Diop).The Chiraphos ligand causes a decrease of the catalytic activity with respect to Diop.Optical yields for rhodium catalysts are always higher with Chiraphos, whereas scattered results were obtained with platinum catalysts.Since for the catalytic systems examined asymmetric induction takes place before or during the formation of the intermediate diastereomeric metal alkyl complexes, the results are tentatively rationalized on the basis of a stereochemical model for the transition state leading to the above metal alkyl complexes intermediate.