PROCESS FOR PREPARING 3-EXO-METHYLENECEPHAM DERIVATIVES

摘要

This invention provides a process for preparing a 3-exo-methylenecepham derivative represented by the formula (III) wherein R1 represents an aralkyl or aryloxymethyl group both of which may be substituted on the aromatic ring, and R2 represents a carboxyl-protecting group, the process comprising subjecting a compound represented by the formula (II) wherein R1 and R2 are as defined above, to a cyclization reaction in an acidic water-containing solvent.