The synthetic utility and potential power of the Diels–Alder (D–A) reaction in organic chemistry is evident. These significances have been extended to the synthesis of a plethora and wide variety of heterocyclic compounds via [4 + 2] cycloaddition reactions, the so called hetero Diels–Alder (HDA) reaction. In this work we try to focus on the scope and preparative synthetic applications of the HDA reaction as a key step in the total synthesis of natural products.