Difluoro(phenylchalcogen)methylation of aldehydes, ketones, and imines with S-, Se-, and Te-containing reagents PhXCF ₂H (X = S, Se, Te)

A series of sulfur-, selenium- and tellurium-containing (phenylchalcogen)difluoromethylation reagents PhSCF ₂H (1a), PhSeCF ₂H (1b), and PhTeCF ₂H (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 PhOCF ₂H (1d) was found to be unable to undergo similar fluoroalkylation reactions.