Silver/ThioClickFerrophos-Catalyzed 1,3-Dipolar Cycloaddition and Tandem Addition–Elimination Reaction of Morita–Baylis–Hillman Adducts
Yuko Suzuki, Kazuya Kanemoto, Ayana Inoue, Kazumi Imae, Shin‐ichi Fukuzawa
Abstract
The asymmetric 1,3-dipolar cycloaddition of glycine imino esters to Morita–Baylis–Hillman (MBH) adducts or acetylated MBH adducts is described. The reaction was efficiently catalyzed by AgOAc/(R,Sp)-ThioClickFerrophos at room temperature to afford pyrrolidine derivatives bearing a quaternary carbon as a single diastereomer with excellent enantioselectivity. When a cyclic pyrroline ester was used as the nucleophile instead of a glycine imino ester, the enantioselective tandem addition–elimination reaction with an acetylated MBH adduct proceeded with an excellent yield and enantioselectivity, resulting in the formation of an exo-olefin. The wide substrate scope of these reactions and the transformability of the products enable expeditious access to divergent multifunctionalized pyrrolidines in an optically pure fashion.