Visible-Light-Mediated Radical Cascade Sulfonylation/Trifluoromethylation/Difluoromethylation of Activated Alkenes with Sulfinates towards γ-Carbolinone Derivatives

Abstract

γ-Carboline scaffolds are key structural motifs in various natural products and pharmaceuticals. Herein, we report a novel visible-light-driven, Rose Bengal-catalyzed radical cascade cyclization of N-acryloylindole-3-carboxamides with sulfinates for the synthesis of γ-carboline derivatives. This metal-free protocol enables the efficient one-pot construction of sulfonyl-, trifluoromethyl-, and difluoromethyl-substituted γ-carbolines, affording a library of 90 derivatives in moderate to good yields. Operating under mild and neutral conditions, this strategy eliminates the need for expensive metal catalysts and harsh pH environments, adheres to green chemistry principles, and further expands the application of sulfinates in organic-dye photoredox catalysis.