PROCESS FOR THE SELECTIVE PREPARATION OF 3-(Z) PROPENYL-CEPHEM COMPOUND

摘要

A 3-(Z)-propenyl cephem compound is selectively prepared by reacting a phosphoranylidene cephemcompound with acetaldehyde in the presence of a base in a solvent mixture comprising diethyl ether, formula (I), wherein R is a carboxyl protecting group; R<1> is hydrogen or R<2>CH2CO-; and R<2> is ethyl, 2-thiophenyl, phenyl, p-hydroxyphenyl or phenoxy.