Palladium-Catalyzed Carbonylative [5+1] Cycloaddition of N -Tosyl Vinylaziridines: Solvent-Controlled Divergent Synthesis of α,β- and β,γ-Unsaturated δ-Lactams.

A palladium-catalyzed carbonylative [5+1] cycloaddition of N -tosyl vinylaziridines with CO has been developed. This protocol affords an efficient and practical approach for solvent-controlled divergent synthesis of α,β-unsaturated δ-lactams in dimethylformamide and β,γ-unsaturated δ-lactams in tetrahydrofuran in good to excellent yields. Significantly, the step- and atom-economical reactions are more regioselective toward [5+1] cycloaddition than toward [3+1] cycloaddition.