Tandem [2+4] annulation/aromatization reaction of yne–enones with o-sulfonamidobenzaldehydes

Abstract

Yne–enones are valuable platform molecules that undergo diverse transformations under both metal-catalyzed and metal-free conditions. However, their participation in phosphine-catalyzed annulation reactions has remained relatively unexplored. Herein, a phosphine-catalyzed tandem [2+4] annulation/detosylative aromatization of yne–enones with o-sulfonamidobenzaldehydes is reported, affording polyfunctionalized quinolines in moderate to high yields with a broad substrate scope. A plausible reaction mechanism is proposed, highlighting the potential of yne–enones to serve as versatile synthons for the development of new annulation strategies under phosphine catalysis.