Cycloadditions of ketene acetals under microwave irradiation in solvent-free conditions

Abstract
When subjected to microwave irradiation ketene acetals undergo 1,3-dipolar and hetero-Diels–Alder cycloadditions within 5–12 min to give excellent yields of easily purified heterocyclic products. This efficient and rapid synthesis has the advantage of employing milder reaction conditions than those of classical thermal heating.