Propargyl Alcohols as Bifunctional Reagents for Divergent Annulations of Biphenylamines via Dual C−H Functionalization/Dual Oxidative Cyclization

Quantum leap in the field of C-H functionalization has expediently provided comprehensive solutions to access valuable molecules that previously required convoluted synthetic attempts. Dual C-H functionalization, unsymmetrically, with a single bifunctional reagent is an incisive tactic. Propargyl alcohols (PAs), despite containing reactive C≡C bond, were not however explored as building blocks via oxidative cleavage. Annulations via C-H activation orchestrate versatile and synthetically attractive strategies. In this unprecedented work, we disclose PA as a new bifunctional reagent for unsymmetrical dual C-H functionalization of biphenylamine for regioselectively annulated outcomes. On tuning conditions, the annulation bifurcated towards an unusual dual oxidative cyclization. The methodology accommodates a wide range of PAs and showcases late-stage diversification of some natural products.