Observations on the reaction of cephalosporin V esters with hypervalent lodoarene dihalides

Abstract

Reaction of cephalosporin V esters with 4-t-butyl iodobenzene difluoride is solvent dependent yielding the oxazoline (5) in acetonitrile and the fluorazetidinone (6) in dichloromethane; in contrast, the iodoarene dichloride gives the rearranged isothiazole (9).