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DOI: 10.1055/a-2179-1250
Straightforward Approach to 5-Substituted 7H-Imidazo[2,1-b] [1,3]thiazines via Cyclization of 2-Alkynylthioimidazoles


Abstract
Electrophile-initiated nucleophilic cyclization of 2-alkynylthiobenzimidazoles is a useful tool for synthesizing new heterocyclic systems. However, halogen-initiated cyclization demonstrates poor selectivity between electrophilic addition and substitution reactions using other imidazole analogues. In this research, several different coinage metal catalysts were employed to broaden the scope of 7H-imidazo[2,1-b][1,3]thiazines in atom-economic manner. Selective 6-endo-dig pathway reactions were achieved in good to excellent yields using various 2-alkynylthioimidazoles with AuCl as the catalyst in DCE/DCM.
Key words
alkynes - 6-endo-dig cyclization - imidazoles - heterocycles - ring closure - gold catalysisSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/a-2179-1250.
- Supporting Information
Publication History
Received: 10 July 2023
Accepted after revision: 20 September 2023
Accepted Manuscript online:
20 September 2023
Article published online:
23 October 2023
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