N ¹ ‐Alkylation of Benzotriazoles via Visible‐Light‐Promoted Alkyne–Carbonyl Metathesis

Herein, we describe a photocatalyst‐ and additive‐free three‐component reaction that enables regioselective N 1 ‐alkylation of benzotriazoles. Under visible light irradiation, alkynes and benzoquinones generate para‐quinone methide intermediates in situ, which undergoes subsequent 1,6‐conjugate additions with benzotriazoles. The reaction features mild and efficient conditions, proceeds under light alone, and delivers the alkylated benzotriazoles in up to 98% yield with broad substrate compatibility (34 examples).