Heteroaryl-N-difluoromethyltrimethylsilanes - Versatile sources of heteroaryl-N-difluoromethyl anions in reactions with carbonyl compounds

An efficient procedure for synthesizing heteroaryl-N-difluoromethyltrimethy lsilanes - new nucleophilic difluoromethylene synthons - from easily availa ble N-bromodifluoromethylated heterocycles, chlorotrimethylsilane and alumi nium powder in triglyme or N-methylpyrrolidinone on a preparative scale in 71-75% isolated yield is described. Heteroaryl-N-difluoromethyltrimethylsil anes and benzaldehyde react under fluoride ion catalysis to give 1-(1,1-dif luor-2-hydroxy-2-phenyl-ethyl)heteroaryls whereas for anionic heteroaryl-N- difluoromethylation of cyclohexanone a stoichiometrical mixture of heteroar yl-N-difluoromethyltrimethylsilanes and tetramethylammonium fluoride has to be used.