From One Component Electrocyclic Processes

While the electrocyclic ring-opening of aziridines to azomethine ylides is well known, the reverse reaction has also been studied as a route to aziridines B-83Mi ioi-oi . This process is implicit in the cis-trans equilibration of substituted aziridines 67JA1753, 7UA1779), and may be involved in the reaction of diazoalkanes with imines 84T2569 . Convincing evidence for the electrocyclization of 

Sigmatropic rearrangements of cyclopropylimines 91TL7127 and cyclobutylimines 88H(27)1665 to generate fused bicyclic aziridines have been reported 84CHEC-I(7)47 . The sigmatropic rearrangement of isoxazoles to azirines will be covered in Section 1.01.9.6. Electrocyclic closure of vinyl-nitrenes to azirines will be discussed in Section 1.01.9.5. 

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