Annulative coupling of sulfoxonium ylides with 2-amino(thio)phenols: easy access to 2-acyl benzox(thio)azoles.

A novel method for synthesizing 2-acyl benzothiazoles and benzoxazole derivatives has been developed the annulative coupling of sulfoxonium ylides with 2-aminobenzenethiol and 2-aminophenol derivatives, respectively. This metal-free, one-pot protocol employs elemental sulfur as a mediator to efficiently construct C-N, C-S, or C-O bonds and demonstrates a broad range of functional group compatibility. The potential utility of this approach is further demonstrated through large-scale reactions and the synthesis of some bioactive compounds.