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

Two electrophilic monofluoromethylating reagents, monofluoromethyl(phenyl)sulfonium bis(carbomethoxy)methylide ( 3 a ) and monofluoromethyl(4‐nitrophenyl)sulfonium bis(carbomethoxy)methylide ( 3 b ), 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.