Nucleophilic Substitution of gem-Difluoroalkenes with TMSNu Promoted by Catalytic Amounts of CsCO.

The efficient and practical nucleophilic cyanation and trifluoromethylation with appropriate trimethylsilyl nucleophiles were developed. Catalytic amounts of cheap and nontoxic CsCO were used to maintain a sufficiently high concentration of nucleophilic anion (CN or CF) which could begin the catalytic cycle. The present methodologies provide diverse functionalized monofluoroalkenes bearing a cyano and trifluoromethyl group with excellent to moderate stereoselectivities.