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 with moderate to high yields.