One-Step Synthesis of Complex Nitrogen Heterocycles from Imines and Alkyl-Substituted Maleic Anhydrides

Substituted maleic anhydrides react with imines to form polycyclic lactam products. Diastereoselectivity can be controlled by altering the reaction conditions in some cases, and regiochemistry is dictated by the structure of the allylic substituents on the anhydride. Cyclic imines, including dihydro-β-carbolines and dihydroisoquinolines, exhibit the highest level of reactivity in these new annulation reactions.