Stereoselective Synthesis of gem-Difluoromethylenated Linear Azatriquinanes

Abstract

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The stereoselective synthesis of gem-difluoromethylenated linear azatriquinanes is described herein. The fluoride-catalyzed nucleophilic addition of PhSCF2SiMe3 (1), exploited as a gem-difluoromethylene (-CF2-) building block, to chiral phthalimide 2 provided the corresponding gem-difluoromethylenated adduct 3 in high yield as a diastereomeric mixture. The stereoselective intramolecular radical cyclization of 3 furnished chiral linear azatriquinanes 4, the hydroxy group of which subsequently underwent nucleophilic substitution by organosilanes to provide 5 with high stereoselectivity. Treatment of 5 with Grignard reagents or a reducing agent provided a collection of chiral gem-difluoromethylenated linear azatriquinanes 6–8.