Tetra-substituted furans by a gold-catalysed tandem C(sp3)–H alkynylation/oxy-alkynylation reaction

Abstract

A gold-catalysed cascade C(sp³)–H alkynylation/oxy-alkynylation of acceptor-substituted carbonyl compounds with hypervalent iodine(III) reagents for the synthesis of tetra-substituted furans is described. This reaction involves two Au(I)/Au(III) catalytic cycles and proceeds through a C(sp³)–H alkynylation of a substituted ketone and a subsequent oxy-alkynylation of the generated 2-alkynyl ketone. This mild and simple method can tolerate a wide range of functionalities, offering distinct advantages over previous methods using PIDA as the external oxidant. Furthermore, a gram-scale synthesis is feasible and the synthesized furan product was readily transformed into other related compounds.