Transition metal-free difunctionalization of unactivated alkenes: Arylation/azidation, arylation/chlorination, and arylation/cyanation

Abstract

Arylethylamines represent a privileged scaffold in pharmaceutical compounds and form the backbone of many medical drugs, including those used for treating neurological diseases and pain. Their biomedical significance has inspired new synthetic methods that rely on transition metal-catalyzed aminoarylation reaction to an alkene, often in conjunction with a photoredox catalyst or a photosensitizer and guided by a directing or stabilizing group. Here, we introduce a simple and effective method for the azidoarylation of unactivated alkenes under transition metal-free conditions. Visible- or near-UV-light irradiation of readily available triarylbismuth dichlorides generates an aryl radical that selectively adds to the alkene, and the resulting homobenzyl radical is intercepted by an amine equivalent. This method offers a broad substrate scope and also enables the arylchlorination and arylcyanation of unactivated alkenes.