Gold(I)‐Catalyzed Synthesis of Benzofurans from Tetrahydropyranyl (THP) Ethers of o‐Alkynylphenols

Abstract The activation of π‐systems in alkenes and alkynes by homogeneous gold catalysts is a powerful tool for the synthesis of benzo‐fused heterocycles. Decades of development in the area of gold catalysis have brought an array of new catalysts and with them the discovery of new modes of carbophilic activation of π‐systems in alkenes and alkynes, and investigations of previously unknown mechanistic pathways. In alignment with these efforts, we report a cyclization of tetrahydropyranyl ethers of 2‐alkynylphenols to form benzofurans catalyzed by a gold(I)–NHC complex. The reaction proceeds efficiently at very low catalyst loadings, and the products form in good yields.