C3 Sulfenylation of N‐Heteroarenes in Water under Catalyst‐Free Conditions

• Published in: European journal of organic chemistry Vol. 2017; no. 25; pp. 3646 - 3651
• Main Authors: Ravi, Chitrakar, Joshi, Abhisek, Adimurthy, Subbarayappa
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 07.07.2017; Wiley Subscription Services, Inc
• Subjects: Catalyst free; Catalysts; Chemistry; Chemistry, Organic; C–H functionalization; Feasibility studies; Heterocycles; Hogs; Indoles; Physical Sciences; Pyridines; Science & Technology; Sulfur; Water chemistry; SYSTEM; Heterocycles; Water chemistry; ARYL SULFONYL HYDRAZIDES; Catalyst-free; REGIOSELECTIVE SULFENYLATION; HYDROAMINATION; C-H functionalization; H BOND FUNCTIONALIZATION; INDOLES; ELEMENTAL SULFUR; Sulfur; THIOSULFONATES; SULPHENYLATION; IMIDAZOHETEROCYCLES
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201700487

A method for the catalyst‐free C–H sulfenylation of imidazo[1,2‐a]pyridines by using sulfonothioates as an odorless thioarylated reagent in aqueous medium was developed. This protocol was used for a variety of substituted imidazo[1,2‐a]pyridines with broad functional‐group tolerance and was extended to the sulfenylation of indoles and imidazothiazoles. The sulfonothioates were activated exclusively in aqueous medium rather than in an organic solvent, and the feasibility of the process for scale‐up studies was demonstrated. The synthesis of sulfenylated imidazo[1,2‐a]pyridines, phenylbenzo[d]imidazo[2,1‐b]thiazoles, and indole derivatives under catalyst‐free, aqueous conditions is reported. A high level of functional‐group tolerance is shown by this reaction, and the scope of this sulfenylation protocol is extended to a variety of arene‐ and alkanesulfonothioates.