Silver-Free Palladium-Catalyzed sp³ and sp² C–H Alkynylation Promoted by a 1,2,3-Triazole Amine Directing Group

Abstract

Triazole amine was identified as an effective directing group in promoting C-H alkynylation under silver-free conditions. No other external oxidant was required, and the alkynylation products were received in good to excellent yields. X-ray crystallographic analysis confirmed a direct C-H activation intermediate. Other typical directing groups, including pyridine amine (PIP) and 8-aminoquinoline (QA), gave almost no reaction under identical conditions, which highlighted the unique reactivity of the triazole directing group in direct C-H functionalization.