Gu ZY, Cao JJ, Wang SY, Ji SJ. The involvement of the trisulfur radical anion in electron-catalyzed sulfur insertion reactions: facile synthesis of benzothiazine derivatives under transition metal-free conditions.
Chem Sci 2016;
7:4067-4072. [PMID:
30155050 PMCID:
PMC6013918 DOI:
10.1039/c6sc00240d]
[Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/03/2016] [Indexed: 11/21/2022] Open
Abstract
An efficient and practical synthesis of benzothiazine by K2S initiated sulfur insertion reaction with enaminones via electron catalysis is developed. This protocol provides a new, environment-friendly and simple strategy to construct benzothiazine derivatives via formation of two C-S bonds under transition metal-free, additive-free and oxidant-free conditions. K2S not only provides the sulfur insertion source, but also ignites the reaction through the formation of a trisulfur radical anion and electrons in DMF.
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