Enantioselective Cascade Catalysis for the Construction of Tetrahydroquinolines.

Secondary amines are widely used as robust catalysts for the enantioselective functionalization of aldehydes, yet they are rarely employed as Lewis bases or hydrogen-bonding catalysts for alkene activation. In this study, we present a decarboxylative [4 + 2] cycloaddition of vinyl benzoxazinanones with nitroolefins to construct tetrahydroquinolines through cascade catalysis. A single chiral morpholine catalyst sequentially functions as both a Lewis base and a hydrogen-bonding catalyst. These activation modes effectively drive the cascade process and control the stereochemistry.