Mild electrophilic trifluoromethylation of beta-ketoesters and silyl enol ethers with 5-trifluoro methyldibenzothiophenium tetrafluoroborate.

TLDR: 5-trifluoromethyldibenzothiophenium tetrafluoroborate and tetrabutylammonium d ifluorotriphenylstannate were used for efficient electrophilic trifleoromethylation of various silyl enol ethers leading to the corresponding alpha-trIfluorometrichyl ketones in good to high yields.

Abstract: Cyclic and acyclic β-ketoesters were efficiently trifluoromethylated with 5-trifluoromethyldibenzothiophenium tetrafluoroborate in the presence of a phase-transfer catalyst to afford the corresponding α-substituted α-trifluoromethyl β-ketoesters in good to excellent yields. In a second approach, 5-trifluoromethyldibenzothiophenium tetrafluoroborate and tetrabutylammonium difluorotriphenylstannate were used for efficient electrophilic trifluoromethylation of various silyl enol ethers leading to the corresponding α-trifluoromethyl ketones in good to high yields.