Regioselective Synthesis of Fused Furans via Decarboxylative Annulation of α,β-Alkenyl Carboxylic Acid with Cyclic Ketone: Synthesis of Biheteroaryl Derivatives.

alpha,beta-Alkenyl carboxylic acids undergo Cu-II-mediated decarboxylative annulation reactions with aliphatic cyclic ketones to provide synthetically valuable di-heterocycles. The annulation process tolerates a variety of aliphatic ketones and heterocyclic alkenyl carboxylic acids, producing substituted fused furan derivatives with complete regioselectivity. The current protocol offers a synthetically applicable pathway to construct a variety of oligo-heterocycles through Cu-mediated single-electron transfer and decarboxylation. Notably, synthesis of relatively inaccessible di-heterocycles has been achieved successfully using this protocol.