Intramolecular Imino-ene Reaction of Azirines: Regioselectivity, Diastereoselectivity, and Computational Insights

Intramolecular imino-ene reaction of 2H-aziridine has been studied experimentally and computationally, demonstrating that (1) the concerted process takes place regioselectively on the alkene E-CH group; (2) the geometry of the N-linker impacts the reaction activation energy and diastereoselectivity significantly, with pyramidal alkyl amine as the linkage, an exclusive cis-product is achieved; (3) when the reaction has to occur with the Z-CH group, the cis-diastereoselectivity is solely observed regardless of the nature of the N-linkage.