Photocatalytic coupling of amines to imidazoles using a Mo–ZnIn2S4 catalyst†
Substituted imidazoles are traditionally synthesized by co-condensation of multiple feedstocks. Herein, we report a new route for the synthesis of substituted imidazoles via photocyclization of readily available amines at room temperature. The reaction is achieved by the visible-light-induced C–C/C–N bond coupling and subsequent dehydrogenation reaction over Mo–ZnIn2S4 as a heterogeneous photocatalyst. A wide range of amines were converted into the corresponding tri- and tetra-substituted imidazoles with up to 96% total yields. The simplicity, high efficiency and mild condition merits of this new reaction will enable it to be useful in synthetic transformations.