Enantioselective synthesis of Amaryllidaceae alkaloids (+)-vittatine, (+)-epi-vittatine, and (+)-buphanisine

Abstract

Cat. on a hot tin roof: Enantioselective catalytic Michael addition of α-cyanoketones to acrylates under bifunctional organocatalysis was used to construct the unique arylic all-carbon quaternary stereocenter, which is synthetically crucial in the chemical synthesis of optically pure cis-aryl hydroindole alkaloids. The protocol offers an asymmetric route to (+)-vittatine, (+)-epi-vittatine, and (+)-buphanisine.

Keywords: Michael addition; alkaloids; asymmetric synthesis; organocatalysis; quaternary carbon.