Photocatalyst-, metal- and additive-free regioselective radical cascade sulfonylation/cyclization of benzimidazole derivatives with sulfonyl chlorides induced by visible light?

Organic Chemistry Frontiers Pub Date: 2022-05-24 DOI: 10.1039/D2QO00518B

Abstract

Herein, an environmentally friendly and practical protocol for the visible-light-triggered regioselective radical cascade sulfonylation/cyclization of unactivated alkenes towards the synthesis of polycyclic benzimidazoles containing the sulfone group has been developed. Notably, the control experiments demonstrated that a radical pathway was involved in this reaction, and a sulfonyl radical center was initially generated via self-homolysis of sulfonyl chloride upon irradiation. Moreover, this protocol features a wide substrate scope, high atom economy, and excellent regioselectivity, and is easy to scale up.

Graphical abstract: Photocatalyst-, metal- and additive-free regioselective radical cascade sulfonylation/cyclization of benzimidazole derivatives with sulfonyl chlorides induced by visible light
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