Ruthenium- and enzyme-catalyzed dynamic kinetic resolution of secondary alcohols

Enzymatic resolution of secondary alcohols under substrate racemizing condi tions was studied using an immobilized lipase from Candida antarctica in th e presence of a ruthenium catalyst. A specifically designed acyl donor, 4-c hlorophenyl acetate, was found to be compatible with both catalysts and res ulted in an efficient dynamic kinetic resolution. Studies of the reaction i n different solvents showed that nonpolar solvents gave the best results. W ith this process, a variety of racemic secondary alcohols were transformed to the corresponding enantiomerically pure acetates, making efficient use o f all starting material. In most cases, the reaction proceeded with >99% ee and in good yield.