Asymmetric transformations of acyloxyphenyl ketones by enzyme-metal multicatalysis

A multipathway process comprising several enzyme- and metal-catalyzed reactions has been explored for the asymmetric transformations of acyloxyphenyl ketones to optically active hydroxyphenyl alcohols in the ester forms. The process comprises nine component reactions in three pathways, all of which take place by the catalytic actions of only two catalysts, a lipase and a ruthenium complex. The synthetic reactions were carried out on 0.2-0.6 mmol scales for eight different substrates under an atmosphere of hydrogen (1 atm) in toluene at 70 degrees C for 3 days. In most cases, the yields were high (92-96%) and the optical purities were excellent (96-98% ee), This work thus has demonstrated that enzyme-metal multicatalysis has great potential as a new methodology for asymmetric transformations.