K₂S₂O₈-KI Cooperative Oxidative System for Direct C3-Sulfenylation of Indoles with Thiols and Disulfides

Abstract

A mild and metal-free method for the direct C3-sulfenylation of indoles using a KI/K₂S₂O₈ oxidative system has been developed. The reaction proceeds efficiently in MeCN/H₂O at 60 °C, affording 3-sulfenylindoles in up to 95% yield without the need for transition metals or bases. A wide range of indole derivatives and aromatic sulfenylating agents bearing electron-donating or electron-withdrawing substituents are well tolerated. This protocol provides an efficient, scalable, and environmentally benign approach to the synthesis of 3-sulfenylindoles under simple operational conditions.

Keywords

Sulfenylation - C–S bond formation - Sulfenylindoles - Disulfides - Thiols

Publication History

Received: 18 November 2025

Accepted after revision: 14 January 2026

Accepted Manuscript online:
18 January 2026

Article published online:
12 February 2026

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