Desymmetrisation of prochiral ketones using lipases

This review summarises recent advances in the use of lipase enzymes for the desymmetrisation of prochiral ketones. The method employed involves chemical conversion of the ketone to the racemic enol acetate followed by lipase-catalysed transesterification with n-butanol. A system for recycling the ketone in one-pot has been demonstrated and resulted in a high yield of a key enol ester intermediate for the synthesis of an important tachykinin NK-2 antagonist. 1,5-Disubstituted-8-oxabicyclo [3.2.1] octanones and 4,4-disubstituted cyclohexanones have been studied in detail and absolute configurations of two of the enzymatically derived enol esters determined.