ChemInform Abstract: Catalytic Approaches to the Synthesis of β-Lactamase Inhibitors.

Abstract

Abstract Catalytic couplings were utilized to stereospecifically synthesize several 7 E - and 7 Z -alkylidenecephalosporins. Members of this class are known inhibitors of β-lactamase. Zinc/NH 4 Cl reduction of dibromide 14 stereospecifically produced E -monobromide, 15 . In contrast, treatment of 14 with isopropylmagnesium bromide, followed by mild acid, stereospecifically produced Z -monobromide 27 . These reactions involve stable, intermediate α-(metalloalkylidene)-β-lactams. Monobromides 15 and 27 were stereospecifically coupled to organostannanes, or were converted to the corresponding organostannanes, 22 and 32 , which coupled with organohalides.