Ruthenium-Catalyzed Diastereoselective Synthesis of Fully Substituted Pyrrolidines from Anilines and Diazo Pyruvates

An unprecedented synthesis of polysubstituted pyrrolidines from anilines and diazo pyruvates by ruthenium catalysis under mild reaction conditions is reported. An enol intermediate derived from the N-H insertion of aniline toward the ruthenium carbene species as well as an imine ester intermediate generated by SET-mediated oxidation of enol were proposed as the key intermediates. This strategy provides various pyrrolidines containing four contiguous stereocenters in good efficiency with high diastereoselectivities.