Synthesis of Trifluoromethylated Pyridines and Quinolines Using Me₃SiCF₃

Significance

A new type of nucleophilic trifluoro­methylation of pyridines and quinolines is reported involving treatment of N-alkylazinium salts with Ruppert’s reagent, Me₃SiCF₃ in the presence of KF. The method consists of three steps: i) conversion of the azine into the PMB salt, ii) addition of Me₃SiCF₃, and iii) oxidation of the dihydroazines to the corresponding aromatic azines. The KF generates the reactive species by reaction with Ruppert’s reagent and Ph₃SnF is used as a phase-transfer catalyst. With expansion of the substrate scope, the reaction may become a valuable addition to the available trifluoromethylation methods (see book below).