The Asymmetric Synthesis of Polycyclic Tetrahydroxanthone via the Cascade Reaction of Alkene‐Substituted 1,3‐diketones and Alkenyloxindoles

Abstract

An enantioselective access to polycyclic tetrahydroxanthone compounds was achieved through an organocatalyzed cascade reaction of alkene‐substituted 1,3‐diketones and alkenyloxindoles, using quinine‐derived squaramide as an efficient catalyst. It afforded a variety of optically active spirooxindole‐based tetrahydroxanthones with 18‐94% yields, >19:1 dr, and 86‐99% ee.