Assembly of 2-Arylbenzothiazoles through Three-Component Oxidative Annulation under Transition-Metal-Free Conditions

Abstract

Highly efficient methods for the synthesis of 2-arylbenzothiazoles and 2-arylnaphtho[2,1-d]thiazoles have been developed. Readily available aromatic amines, benzaldehydes, and elemental sulfur were directly assembled through oxidative annulation and C-H functionalization under transition-metal-free conditions, where DMSO or oxygen served as the oxidant. NH₄I or KI as the catalyst was found to be effective to promote the transformations to give the annulation products in good to excellent yields with wide functional group tolerance.