Construction of tetrahydropyranoquinoline derivatives via an asymmetric organocatalytic aza-Michael-IED/HAD cascade reaction

Abstract

Chiral functionalized tetrahydroquinolines and pyranoquinolines with multiple stereogenic centres have emerged as attractive structures for derivatizing bioactive complex molecules. Herein, we develop a novel, facile organocatalytic asymmetric aza-Michael-IED/HAD cascade reaction of (E)-ethyl 4-(2-(4-methylphenylsulfon amido)phenyl)-2-oxobut-3-enoate and enals. This method enables a convenient, powerful, and atom-economical access to various desired tetrahydropyranoquinoline derivatives with control of four stereogenic centres in good yields (up to 88%) with excellent diastereo- and enantioselectivities (up to >99 : 1 dr and >99% ee, respectively).