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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.

We present here a rhodium-catalyzed oxidative three-point double annulation of enaminones with propargylic alcohols via a C-H and a C-N bond activation to access arylnaphthalene-based lignan derivatives. The key step in the reaction is the regioselective insertion of propargylic alcohol into the rhoda-cycle, a result of hydroxyl rhodium coordination. Necessary control experiments and KIE studies were conducted to determine the mechanism.

A cascade reaction of enynones with enaminones via cyclative coupling to engineer diverse multisubstituted furans and furano-pyrrole bisheterocycles is described and is proposed to involve carbene insertion and C–C migrations to deliver a totally rearranged product.