Regioselective Synthesis of Fused Furans by Decarboxylative Annulation of α,β‐Alkenyl Carboxylic Acid with Cyclic Ketone: Synthesis of Di‐Heteroaryl Derivatives

α,β‐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.