Diastereoselective Pyrrolidine Formation via Pd(II)-Catalyzed Cyclization of γ -C(sp ³ )–H Bond of Substituted Amino Acids with Morita–Baylis–Hillman Acetate

A highly efficient synthesis of diastereoselective enantiopure alkene-embedded pyrrolidines from substituted amino acids and Morita–Baylis–Hillman acetates is described. The optimized catalytic condition exhibited remarkable selectivity, affording the corresponding pyrrolidine scaffold exclusively despite the presence of multiple β- C–H and β- C–OAc bonds. This methodology was successfully applied to a broad range of amino acid derivatives and MBH acetates. Furthermore, various postsynthetic transformations were performed to demonstrate the synthetic utility by exploiting the intact α,β -unsaturated ester moiety. Finally, detailed mechanistic investigations were carried out to propose a plausible reaction pathway for this unprecedented transformation.