Difluoro(phenylchalcogen)methylation of aldehydes, ketones, and imines with S-, Se-, and Te-containing reagents PhXCF2H (X = S, Se, Te)

A series of sulfur-, selenium- and tellurium-containing (phenylchalcogen)difluoromethylation reagents PhSCF2H (1a), PhSeCF2H (1b), and PhTeCF2H (1c) were prepared, and their relative reactivity towards aldehydes, ketones, and imines was investigated. Compared to the former developed (phenylchalcogen)difluoromethylation reagents, these reagents are relatively easily available and more atom-economical in fluoroalkylation reactions. It was found that the efficient nucleophilic (phenylchalcogen)difluoromethylation of aldehydes, ketones, and imines could be achieved with 1a–1c. Reagents 1a and 1b showed better reactivity than 1c toward carbonyl compounds and imines, and PhOCF2H (1d) was found to be unable to undergo similar fluoroalkylation reactions.

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► PhSCF2H, PhSeCF2H, and PhTeCF2H were successfully applied as efficient (phenylchalcogen)difluoromethylation reagents.
► Aldehydes, ketones, and N-tert-butylsulfinyl imines are amenable to the present (phenylchalcogen)difluoromethylation reaction.
► The F2C–H acidity of these reagents is PhSCF2H < PhSeCF2H ∼ PhTeCF2H.
► The proper use of base and solvent plays an important role in the present (phenylchalcogen)difluoromethylation reaction.