Construction of Eight-Membered Carbocycles through Gold Catalysis with Acetylene-Tethered Silyl Enol Ethers

Semihollow triethynylphosphanes were synthesized and employed as ligands in the gold‐catalyzed 8‐exo‐dig cyclization of acetylene‐tethered silyl enol ethers to obtain eight‐membered‐ring carbocycles (see scheme). The gold–phosphane catalysts promoted either the annulation toward bicyclic structures or the cyclization of acyclic molecules to form nonfused carbocycles. Tf=Trifluoromethylsulfonyl.