Synthesis of Optically Active 2H‐Thiopyrano[2,3‐b]quinolines with Three Contiguous Stereocenters via an Organocatalytic Asymmetric Tandem Michael–Henry Reaction

Abstract

AbstractOptically active 2H‐thiopyrano[2,3‐b]quinolines with three contiguous stereocenters have been synthesized via a chiral bifunctional squaramide‐catalyzed tandem Michael–Henry reaction between 2‐mercaptoquinoline‐3‐carbaldehydes and nitroolefins. The reactions proceed with excellent diastereo‐ and enantioselectivity to give the title compounds in high yields with high levels of diastereo‐ and enantioselectivity (up to >99/1 dr and >99% ee, respectively).