Enantioselective [2 + 2] cycloaddition of 1,2-dihydroquinolines with 3-olefinic oxindoles via Brønsted acid catalysis

A highly diastereo- and enantioselective Brønsted acid-catalyzed [2 + 2] cycloaddition generating heterocyclic products with four contiguous stereocenters in good to excellent yields with high stereoselectivities is reported.