Gold-Catalyzed C(sp3)-H/C(sp)-H Coupling/Cyclization/Oxidative Alkynylation Sequence: A Powerful Strategy for the Synthesis of 3-Alkynyl Polysubstituted Furans

In sharp contrast to the gold-catalyzed reactions of alkynes/allenes with nucleophiles, gold-catalyzed oxidative cross-couplings and especially C-H/C-H cross-coupling have been under represented. By taking advantage of the unique redox property and carbophilic pi acidity of gold, this work realizes the first gold-catalyzed direct C(sp(3))-H alkynylation of 1,3-dicarbonyl compounds with terminal alkynes under mild reaction conditions, with subsequent cyclization and in situ oxidative alkynylation. A variety of terminal alkynes including aryl, heteroaryl, alkenyl, alkynyl, alkyl, and cyclopropyl alkynes all successfully participate in the domino reaction. The protocol offers a simple and region-defined approach to 3-alkynyl polysubstituted furans.