Stereoselective Total Synthesis of (+)-Toussaintines C and H and Their Enantiomers via a Chiral Sulfinamide Auxiliary Strategy

초록

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.

키워드