Abstract The Diels-Alder reaction of 2-substituted 4-(trimethylsilyloxy) oxazoles, which were prepared in situ from trimethylsilyldiazomethane and acyl isocyanates, with dimethyl acetylenedicarboxylate or ethyl propiolate gave furan-3, 4-dicarboxylic or furan-3-carboxylic esters in good yields.
