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

The C−H functionalization strategy provides access to valuable molecules that previously required convoluted synthetic attempts. Dual C−H unsymmetrical functionalization, with a single bifunctional reagent, is an effective tactic. Propargyl alcohols (PAs), despite containing a reactive C≡C bond, have not been explored as building blocks via oxidative cleavage. Annulations via C−H activation are a versatile and synthetically attractive strategy. We disclose PA as a new bifunctional reagent for unsymmetrical dual C−H functionalization of biphenylamine for regioselectively annulated outcomes. On tuning the conditions, the annulation bifurcated towards an unusual dual oxidative cyclization. This method accommodates a wide range of PAs and showcases late‐stage diversification of some natural products. A palladium‐catalyzed divergent and regioselective annulation of biphenylamines with propargyl alcohols (PAs) is demonstrated. These annulations run through an unsymmetrical dual C−H functionalization via a C≡C bond cleavage, or through a dual oxidative cyclization. The method accommodates a wide range of PAs and showcases late‐stage diversification of some natural products.