Cesium fluoride catalyzed trifluoromethylation of esters, aldehydes, and ketones with (trifluoromethyl)trimethylsilane

The low reactivity of carboxylic esters toward (trifluoromethyl)trimethylsi lane (TMS-CF3) was investigated. A universal cesium fluoride catalyzed proc edure for nucleophilic trifluoromethylation was developed. At room temperat ure (25 degrees C), with catalytic amounts of cesium fluoride, carboxylic e sters were found to react to give the silyl ether intermediates, which affo rded the trifluoromethyl ketones after hydrolysis. Sulfonic, sulfinic, and selenic esters also show good reactivity, giving novel trifluoromethylated compounds. The trifluoromethylation method was also applied to aldehydes an d ketones, which were transformed to trifluoromethyl silyl ether intermedia tes and afforded trifluoromethylated alcohols in excellent yields after aci d hydrolysis. Ethylene glycol dimethyl ether was used as solvent for solid or high boiling substrates, and benzonitrile was used for the low boiling s ubstrates.