In the realm of transition-metal catalyzed arene functionalization, rhodium(III) catalysis is considered as exemplary due to its propensity to activate C−H bonds to obtain comprehensive molecular assembly. Herein, we demonstrate a new rhodium(III) catalyzed assembly of polyheterocyclic scaffolds via C−H activation and regioselective annulation of 4-arylbut-3-yn-1-amines with 4-hydroxy-2-alkynoates. Heterocyclization and transmetalation prior to annulation is the key for initiation of this relay redox-neutral catalytic cascade.

Given their omnipresence in natural products and pharmaceuticals, isochromenone congeners are one of the most privileged scaffolds to synthetic chemists. Disclosed herein is a dual (ortho/meta) C−H and C−C activation of phenacyl ammonium salts (acylammonium as traceless directing group) toward annulation with propargylic alcohols to accomplish rapid access for novel isochromenones by means of rhodium catalysis from readily available starting materials. This operationally simple protocol features broad substrate scope and wide functional group tolerance. Importantly, the protocol circumvents the need of any stoichiometric metal oxidants and proceeds under aerobic conditions.

Enynes have recently stimulated enormous attention toward paving the way to unique cascade cyclizations offering complex cyclic motifs from linear substrates. We describe herein a general approach to napthyridinones via the Pd-catalyzed annulation of 1,6-enynes with 2-iodoanilines. This protocol represents a rare carbo-aminative annulative cyclization via the 6-endo-trig mode, subduing the well-documented exo-trig/dig cyclizations. The regioselective aryl palladation of alkyne followed by Heck-type intramolecular coupling before isomerization were key in realizing this cascade.