Regioselective synthesis of polysubstituted pyridines via hetero-Diels–Alder reaction of isotellurazoles with acetylenic dienophiles

Treatment of substituted isotellurazoles or their Te-oxides with acetylenic dienophiles efficiently afforded polysubstituted pyridine derivatives through a pathway involving hetero-Diels–Alder reaction of isotellurazoles and the subsequent tellurium extrusion from the intermediary cycloadducts.