Copper(I)-catalyzed benzylation of triazolopyridine through direct C–H functionalization

A general and efficient copper-catalyzed benzylation reaction of triazolopyridine with N-tosylhydrazones was developed. This reaction forms C(sp2)-C(sp3) bond through cross-coupling, and represents an exceedingly practical method to afford 3-benzylated triazolopyridines in moderate to good yields,. A proposed mechanistic pathway underlying this reaction was outlined. This catalytic transformation should enable borad synthetic applications in functionalization chemistry, allowing the synthesis of new pharmaceutically relevant trizaolopyridine derivatives.