Mild electrophilic trifluoromethylation of beta-ketoesters and silyl enol ethers with 5-trifluoro methyldibenzothiophenium tetrafluoroborate.
Cyclic and acyclic beta-ketoesters were efficiently trifluoromethylated with 5-trifluoromethyldibenzothiophenium tetrafluoroborate in the presence of a phase-transfer catalyst to afford the corresponding alpha-substituted alpha-trifluoromethyl beta-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 alpha-trifluoromethyl ketones in good to high yields.
UMR 6014 de l'IRCOF (Institut de Recherche en Chimie Organique Fine), Université de Rouen, 1 Rue Tesnière, F-76821 Mont Saint Aignan, France.
Jun-An
JA
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Dominique
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Cahard