the preparation of trifluoromethyl N-acyl sulfilimines to the case of bromodifluoro- and dichlorofluoromethyl derivatives. Attempts to convert such N-acyl sulfilimines to free NH-sulfilimines failed. However, a strategy based on the reaction of their direct ditriflyl ketal precursor with amines allows the isolation of either original sulfilimino iminium salts using secondary amines or of free NH-sulfilimines
original route to Hu's reagent. Unprecedented chlorofluoromethyl sulfoximines have been also isolated, and these compounds have been shown to act as an electrophilic source of this original bis-halogenated moiety. The mechanism of the electrophilic chlorofluoromethylation is also discussed.