Diastereo- and enantioselective construction of an indole-based 2,3-dihydrobenzofuran scaffold via catalytic asymmetric [3+2] cyclizations of quinone monoimides with 3-vinylindoles

The first catalytic asymmetric [3+2] cyclization of quinone monoimides with olefins has been established, which employed 3-vinylindoles as a class of competent olefins and spiro-chiral phosphoric acid as a powerful chiral catalyst, leading to chemo-, diastereo- and enantioselective construction of a biologically important 2,3-dihydrobenzofuran framework with optical purity (up to 99% yield, 495: 5 dr, 96: 4 er).