Synthesis of 3-alkenyl-Δ3-cephems was performed successfully by cross-coupling 3-(trifluoromethylsulfonyloxy or chloro)-Δ3-cephem with alkenyl halides, e.g., vihyl bromide, trans-1-bromo-1-propene, and trans-β-bromostyrene in an Al/cat·PbBr2/cat·NiBr2(bpy)/NMP (or DMF) system. Reduction of 3-(trifluoromethylsulfonyloxy)-Δ3-cephem into norcephalosporin was also achieved by a similar reaction in the presence of 5 molar equiv of water. Scope and a plausible mechanism of the Al/Pb/Ni triplemetal-redox promoted reactions are discussed.
ASJC Scopus subject areas
- Organic Chemistry