Monofluoromethyl-Substituted Sulfonium Ylides: Electrophilic Monofluoromethylating Reagents with Broad Substrate Scopes

Two electrophilic monofluoromethylating reagents, monofluoromethyl(phenyl) sulfonium bis(carbomethoxy)methylide (3a) and monofluoromethyl(4-nitrophenyl)sulfonium bis(carbomethoxy)methylide (3b), and their reactions under mild conditions with a variety of nucleophiles, such as alcohols and malonate derivatives, sulfonic and carboxylic acids, phenols, amides, and N heteroarenes, are described. Mechanistic studies with deuterated reagents [D-2]3 a/[D-2]3 b suggest that these monofluoromethylation reactions proceed through an electrophilic substitution pathway.