Base-Promoted Reaction between N-Acyl Benzotriazoles and p-Toluenesulfonylmethyl Isocyanide (TosMIC): A Facile Synthesis of 4,5-Disubstituted Oxazoles

We herein developed a base-promoted cyclization reaction between N-acyl benzotriazoles and p-toluenesulfonylmethyl isocyanide (TosMIC) to afford 4,5-disubstituted oxazoles. In the presence of 3 equiv of K3PO4, the two readily available starting materials reacted in N,N-dimethylformamide at 80 °C to give 28 examples of 4-tosyl-5-aryl, -alkyl, or -alkenyl-substituted oxazoles in moderate to high yields.