Preparation of an optically pure secondary alcohol of synthetic pyrethroids using microbial lipases

Enzyme-catalysed hydrolysis of esters of 4-hydroxy-3-methyl-2-(2-propynyl)-cyclopent-2-enone (HMPC) was examined for the preparation of the optically pure alcohol moiety of synthetic pyrethroids. Arthrobacter lipase gave the optically pure (R)-HMPC at 50% hydrolysis in a two-liquid phase reaction system of water and the insoluble substrate. The hydrolysis proceeded even at a substrate concentration of 80 w/v%. The enantioselectivity was not changed with the chain length of the acid moiety of the esters. By combination of the enzymatic resolution with a chemical inversion of the (R)-alcohol, an efficient process was developed for the total conversion of racemic HMPC to (S)-HMPC, which is an important alcohol for preparation of an insecticidally-active synthetic pyrethroid.