We report the first examples of intramolecular Diels-Alder addition of heterodienophiles N= N, CN, C-0, C 4 to oxazoles. The required ðoxy-and bphenyloxazoles were synthesized bearing a side chain of variable length on C-2 to which the different heterodienophiles are attached. The products of the thermal bis heteroannulation are 3-triazolines, imidazolines, oxazolines, or thiazolines fused to a five-to six-membered ring. Relative reactivities were ...
