Elemental Sulfur Participates in the Decarboxylative Coupling of Oxidized 2-Aminophenol and Phenylglyoxylic Acid

A simple and practical elemental sulfur-catalyzed one-pot method for the synthesis of benzoxazole derivatives has been developed. The protocol uses inexpensive elemental sulfur as the catalyst and highly effective to promote this transformation without the aid of any metal salts. The corresponding benzoxazoles were achieved in good to high yields. Compared with previous methods, becouse of elemental sulfur promoted decarboxylative cyclization was unique and allow highly flexible and wide range of applications displays great potential for replacing existing methodologies.