Intramolecular hydroamination of alkynic sulfonamides catalyzed by a gold–triethynylphosphine complex: Construction of azepine frameworks by 7-exo-dig cyclization

• Hideto Ito,
• Tomoya Harada,
• Hirohisa Ohmiya and
• Masaya Sawamura

Beilstein J. Org. Chem. 2011, 7, 951–959, doi:10.3762/bjoc.7.106

• investigated. The protocol, with a semihollow-shaped triethynylphosphine as a ligand for gold, allowed the synthesis of a variety of azepine derivatives, which are difficult to access by other methods. Both alkynic sulfoamides with a flexible linear chain and the benzene-fused substrates underwent 7-exo-dig

• cyclization to afford the nitrogen-containing heterocyclic seven-membered rings, such as tetrahydroazepine and dihydrobenzazepine, in good yields. Keywords: azepine; cyclization; gold catalyst; hydroamination; triethynylphosphine; Introduction Nitrogen-containing heterocyclic seven-membered rings are found

• heterocyclic seven-membered rings, and we applied the triethynylphosphine–gold(I) catalytic systems to the synthesis of azepine derivatives through intramolecular hydroamination of alkynic sulfonamides. This article describes the results of the optimization of reaction conditions, exploration of substrate