Ito H, Harada T, Ohmiya H, Sawamura M. Intramolecular hydroamination of alkynic sulfonamides catalyzed by a gold-triethynylphosphine complex: Construction of azepine frameworks by 7-exo-dig cyclization.
Beilstein J Org Chem 2011;
7:951-9. [PMID:
21915193 PMCID:
PMC3167492 DOI:
10.3762/bjoc.7.106]
[Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Accepted: 06/17/2011] [Indexed: 11/23/2022] Open
Abstract
The gold-catalyzed, seven-membered ring forming, intramolecular hydroamination of alkynic sulfonamides has been 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.
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