Facile synthesis of chiral [2,3]-fused hydrobenzofuran <i>via</i> asymmetric Cu(<scp>i</scp>)-catalyzed dearomative 1,3-dipolar cycloaddition

Abstract

Intermolecular asymmetric dearomative 1,3-dipolar cycloaddition of 2-nitrobenzofurans with azomethine ylides was enabled by using a chiral Cu(i)/(S,Sp)-iPr-Phosferrox catalyst. As a result, a series of highly stereoselective chiral [2,3]-fused hydrobenzofurans possessing four contiguous stereogenic centers were obtained with good to high yields, diastereoselectivities and enantioselectivities. The reaction has broad substrate scope tolerating various functional groups.