Copper-catalyzed regioselective C2–H chlorination of indoles with para-toluenesulfonyl chloride?

Organic & Biomolecular Chemistry Pub Date: 2022-05-20 DOI: 10.1039/D2OB00758D

Abstract

A copper-catalyzed, pyrimidine directed regioselective C–H chlorination of indoles with para-toluenesulfonyl chloride (TsCl) has been developed. The reactions proceeded smoothly in the presence of 20 mol% of Cu(OAc)2 as the catalyst and TsCl as the chlorine source, delivering C2-chlorinated indoles with structural diversity in moderate to excellent yields. Mechanistic studies suggested that single electron transfer (SET) from Cu(II) to TsCl accompanied by the release of the p-toluenesulfonyl radical and the related Cu(III)Cl species might be involved in the reactions.

Graphical abstract: Copper-catalyzed regioselective C2–H chlorination of indoles with para-toluenesulfonyl chloride
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