Nucleophilic difluoro(phenylsulfonyl)methylation of carbonyls with PhSO2CF2H reagent in the presence of in situ generated substoichiometric amount of base

The reactions between carbonyl compounds and PhSO2CF2H using substoichiometric amount of base in situ generated from N(TMS)3 and catalytic amount of Me4NF have been investigated. It is found that both enolizable and non-enolizable aldehydes are suitable substrates to undergo nucleophilic difluoro(phenylsulfonyl)methylation. Compared to the previously reported trifluoromethylation of carbonyls with CF3H under the similar reaction conditions, the unique reactivity of PhSO2CF2H is attributed to its higher acidity than CF3H and the reversibility of its addition reaction with ketones under basic conditions.