Direct access to functional phenazines via oxidative annulation of anilines and o-phenylenediamines with a reusable cobalt catalyst

Abstract

Despite the widespread applications of amino phenazines, there is still lacking an efficient method enabling direct and diverse access to such compounds due to the limited availability of feedstocks and the challenge in controlling the synthetic selectivity. Here, by using a strategy of single electron oxidation (SEO) induced tandem dual C–H amination, we report a mild approach addressing the as-described issue via oxidative annulation of readily available anilines and o-phenylenediamines, which proceeds with a broad substrate scope and good functional group tolerance, directly uses primary amines as C–H aminating agents, employs a reusable nitrogen-doped carbon-supported cobalt nanocatalyst (Co-Nx/NC-800) and naturally abundant molecular O₂, and exhibits excellent step and atom efficiency. The developed chemistry offers a practical platform to construct various promising amino phenazines that are difficult to synthesize with the conventional methods, and paves the way to further develop SEO-induced valuable transformations under sustainable heterogeneous base metal catalysis.