PHOSPHINERHODIUM COMPLEXES AS HOMOGENEOUS CATALYSTS. XVI. STEREOSELECTIVE HYDROGENATION OF CYCLIC KETONES

Article abstract of DOI:10.1016/S0022-328X(00)99332-X

Cyclic ketones have been hydrogenated stereoselectively with various phosphinerhodium complexes as catalysts.Systems containing phosphines of high basicity and consequently forming Rh^III dihydrides as active species yielded mainly the thermodynamically more stable alcohol isomers.Catalysts prepared from aryl-type phosphines of low basicity and modified with Et3N, which contain Rh^I monohydrides as active complexes, afforded the less stable alcohol isomers as the major products.The ratio of Rh^III and Rh^I hydrides, which determines the stereoselectivity of the catalysts prepared in situ could be changed by suitable choice of base.