Silver/ThioClickFerrophos-Catalyzed 1,3-Dipolar Cycloaddition and Tandem Addition-Elimination Reaction of Morita-Baylis-Hillman Adducts.

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.