Enantioselective Synthesis of Highly Functionalized 2,3-Dihydrobenzofuran Derivatives via Steric Hindrance-Overcoming Strategy.

Abstract

The asymmetric cycloaddition reaction of p-quinone monoimides is a significant research focus for constructing benzofused heterocycles. However, due to steric effects, achieving efficient cycloaddition at highly sterically hindered site is challenging but practically valuable. Herein, we develop an asymmetric [3 + 2] cycloaddition reaction of p-quinone monoimides with 1-vinylnaphthalen-2-ols and 3-vinylindoles via steric hindrance-overcoming strategy. Binaphthalene-based chiral phosphoric acid catalyzes the asymmetric cycloaddition reaction to synthesize highly functionalized 2,3-dihydrobenzofurans in generally good yields with good to excellent stereoselectivities.