The first example of the 3-position-selective C(sp2)–H trifluoromethylation of pyridine rings was established. 3-Position-selective trifluoromethylation was achieved by the nucleophilic activation of pyridine and quinoline derivatives through hydrosilylation and successive electrophilic trifluoromethylation of the enamine intermediate. This reaction was applicable to perfluoroalkylation at the 3-position of the pyridine rings and late-stage trifluoromethylation of a bioactive molecule. Mechanistic studies indicated that the reaction proceeds via the formation of N-silyl enamine and trifluoromethylated enamine intermediates.
3-Position-Selective C–H Trifluoromethylation of Pyridine Rings Based on Nucleophilic Activation