B(C₆F₅)₃-Catalyzed site-selective N¹-alkylation of benzotriazoles with diazoalkanes

Alkylation of benzotriazoles is synthetically challenging, often leading to mixtures of N¹ and N² alkylation. Herein, metal-free catalytic site-selective N¹-alkylation of benzotriazoles with diazoalkanes is described in the presence of 10 mol% of B(C₆F₅)₃. These reactions provide N¹-alkylated benzotriazoles in good to excellent yields and this protocol is successfully adapted to gram-scale syntheses as well as a derivative with antimicrobial activity.