A mild and selective reduction of β-lactams: Rh-catalyzed hydrosilylation towards important pharmacological building blocks

Four-membered N-heterocyclic compounds exhibit a broad range of pharmacological activities. Herein, we report a useful rhodium-catalyzed protocol for the activation of phenylsilane to reduce tertiary β-lactams. Reaction with the tertiary amides was selective over secondary amides, esters, olefins and nitriles, with no erosion of stereochemistry. A one-pot protocol from commercially available starting materials and a selective reduction of a complex penicillin derivative demonstrate the synthetic utility of this facile procedure. A selective Rh-catalyzed protocol to reduce β-lactams to important pharmacologically active azetidines is presented. Reaction with tertiary amides was selective over secondary amides, esters, olefins and nitriles, with no erosion of stereochemistry. A one-pot protocol from commercially available starting materials and a selective reduction of a complex penicillin derivative demonstrate the high synthetic utility of this procedure.