PROCESS AND ESTER DERIVATIVES FOR PREPARATION OF CEPHALOSPORINS

摘要

This invention relates a process for preparing a compound of formula (I) wherein R<1> is para-nitrobenzyl or allyl; and X is halo, which is useful to prepare 3-cyclic-ether-substituted cephalosporins, from trimethylphosphinic compounds. This invention also relates to compounds useful in such process.