A facile access to 3-allyl- and 3-benzyl-3-cephems via reductive addition/cylization of allenecarboxylate with allyl and benzyl halides in an Al/Pb/Ni redox system
Abstract
A sequential reductive addition/cyclization reaction of allenecarboyxlate, derived from penicillin G, with allyl and benzyl halides was successfully performed by the aid of aluminium metal ad catalytic amounts of PbBr2 and [NiCl2(bipy)] to afford 3-allyl- and 3-benzyl-3-cephems, respectively.