Nucleophilic difluoromethylation of aromatic aldehydes using trimethyl (trifluoromethyl)silane (TMSCF3)

Reaction of the Ruppert-Prakash reagent (Me3SiCF3) with aromatic aldehydes in the presence of triphenylphosphine, lithium iodide and lithium tetrafluoroborate selectively furnishes gem-difluorinated phosphonium salts. Simple alkaline hydrolysis of these salts results in difluoromethylated products. Thus, one-pot nucleophilic difluoromethylation of aromatic aldehydes using Me3SiCF3 has been accomplished. The protocol tolerates electron withdrawing as well as electron donating substituents.