SYNTHESIS OF 3-CHLORO-DELTA(3)-CEPHEM-4-CARBOXYLATE BY ADDITION CYCLIZATION OF ALLENECARBOXYLATE - COPPER(II)-PROMOTED AEROBIC OXIDATION OFARENESULFINIC ACIDS/

The selective transformation of allenecarboxylate derived from penicil lin into 3-chloro-Delta(3)-cephem-4-carboxylate was successfully achie ved by an addition/cyclization reaction with chloride salts in aerobic media containing a copper(II) catalysts, in which copper(II)-catalyze d aerobic oxidation of in situ generated benzenesulfinate ion into les s nucleophilic sulfonate ion prior to the nucleophilic addition of the former ion to the allenecarboxylate would completely eliminate the fo rmation of undesired 3-phenylsulfonyl-Delta(3)-cephem-4-carboxylate. U nder similar aerobic conditions, arenesulfinates salts and arenesulfin ic acids were smoothly oxidized to the corresponding sulfonate salts a nd sulfonic acids, respectively.