Stereoselective Synthesis of gem ‐Difluoromethylenated Linear Azatriquinanes

The stereoselective synthesis of gem ‐difluoromethylenated linear azatriquinanes is described herein. The fluoride‐catalyzed nucleophilic addition of PhSCF 2 SiMe 3 ( 1 ), exploited as a gem ‐difluoromethylene (‐CF 2 ‐) 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 .