ABSTRACT Toussaintines are a rare class of N ‐cinnamoylindolidinoid alkaloids derived from Toussaintia orientalis that are distinguished by their multifaceted biological activities and their peculiar occurrence as racemic mixtures. Herein, we present the first enantioselective total syntheses of (+)‐toussaintines C and H, along with their enantiomers. The strategy employed involves Rose Bengal‐mediated oxidative dearomatization and chiral sulfinamide‐controlled intramolecular aza‐Michael cyclization, which resulted in the fused indolidinoid scaffold being endowed with high diastereoselectivity. Subsequent auxiliary cleavage, amide coupling, and chemoselective reduction provided high yields of enantioenriched toussaintines C and H. This stereocontrolled approach enables efficient access to the toussaintine family and its related congeners, as well as facilitating structural confirmation and furthering biological studies.
Kang et al. (Wed,) studied this question.