Synthesis, Reactivity, and Antibacterial Activity of gem-Difluoroalkene, Difluoromethyl, and Trifluoromethyl β-Lactams

New gem-difluoroalkenes were synthesized by the dehydrofluorination of the corresponding 4-CF3-β-lactams. An unexpected rearrangement mechanism of the ester moiety dependent on a stabilizing negative charge was observed. Hydrogenation to 4-CHF2-β-lactams was successful from gem-difluoro-β-lactams.