Organic Photoredox Catalytic Sulfonylation of Enaminones to Access 3-Sulfonyl Chromones

Abstract

Herein, we disclose a readily available phenothiazine derivative as an oxidizing organic photocatalyst, that serves to induce radical cascade sulfonylation/cyclization reaction of enaminones. A variety of 3-sulfonyl chromones have been obtained with moderate to excellent yields. This catalytic platform proceeds under metal-free conditions with a wide substrate scope and broad functional group compatibility, which unlocks the new reactivity of phenothiazine derivatives and adds significant synthetic values to <i>O</i>-heterocycles.