Process for preparing penems

摘要

Compounds of the formula I : wherein R1 represents a hydroxy protecting group and R2 represents a carboxy protecting group, useful as intermediates for the preparation of penem antibiotics, are prepared by hydrolysing a compound of the formula II : wherein R1 and R2 are as defined above and R represents an alkyl, alkenyl or phenylalkyl group having from 1 to 18 carbon atoms, by means of an enzyme capable of se lectively hydrolysing the ester group of the 2-substituent thereof. d