Alkenes are broadly used in synthetic applications, thanks to their abundance and versatility. Ozonolysis is one of the most canonical transformations that converts alkenes into molecules bearing carbon–oxygen motifs via C=C bond cleavage. Despite its extensive use in both industrial and laboratory settings, the aza version—cleavage of alkenes to form carbon–nitrogen bonds—remains elusive. Here we report the conversion of alkenes into valuable amines via complete C=C bond disconnection. This process, which we have termed ‘triazenolysis’, is initiated by a (3 + 2) cycloaddition of triazadienium cation to an alkene. The triazolinium salt formed accepts hydride from borohydride anion and spontaneously decomposes to create new C–N motifs upon further reduction. The developed reaction is applicable to a broad range of cyclic alkenes to produce diamines, while various acyclic C=C bonds may be broken to generate two separate amine units. Computational analysis provides insights into the mechanism, including identification of the key step and elucidating the significance of Lewis acid catalysis.

烯烃因其丰富性和多功能性而广泛用于合成应用。臭氧分解是最典型的转化之一，它通过 C=C 键裂解将烯烃转化为带有碳-氧基序的分子。尽管 aza 版本在工业和实验室环境中得到广泛应用，但 aza 版本（烯烃裂解形成碳氮键）仍然难以捉摸。在这里，我们报道了烯烃通过 C=C 键完全断开转化为有价值的胺的过程。这个过程，我们称之为“三氮杂分解”，是由三氮杂二烯阳离子向烯烃的 （3 + 2） 环加成反应开始的。形成的三唑啉盐接受硼氢化物阴离子中的氢化物，并在进一步还原时自发分解以产生新的 C-N 基序。所开发的反应适用于广泛的环状烯烃以产生二胺，而各种无环 C=C 键可能会断裂以产生两个单独的胺单元。计算分析提供了对机制的见解，包括确定关键步骤和阐明 Lewis 酸催化的重要性。