The facile and stereoselective synthesis of pyrrolidine β-amino acids via copper(i)-catalyzed asymmetric 1,3-dipolar cycloaddition

Abstract

A highly efficient copper(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides with β-phthaliminoacrylate esters was developed under mild conditions, providing the desired pyrrolidine β-amino acid derivatives in high yields (up to 98%) with excellent diastereo- and enantioselectivities (dr >20 : 1, ee up to >99%). Subsequent deprotection and hydrogenolysis of the corresponding cycloadducts could deliver highly functionalized and biologically important free pyrrolidine β-amino acids in a straightforward and efficient pathway.