Thermal and photoinduced reduction of ethyl (Z)-α-cyano-β-bromomethylcinnamate by 1-benzyl-1,4-dihydronicotinamide

Abstract

Thermal and photoinduced reduction of ethyl (Z)-α-cyano-β-bromomethylcinnamate (1) by coenzyme NAD(P)H model 1-benzyl-1,4-dihydronicotinamide (BNAH, 2) gives ethyl (E)-1-cyano-2-phenylcyclopropane-1-carboxylate (3) in the former case, and the (E)-4 and (Z)-5 isomers of ethyl α-cyano-β-methylcinnamate with the (E)-isomer as the major product in the latter case. The results are rationalized in terms of direct hydride transfer and electron transfer–debromination–hydrogen abstraction mechanism, respectively.