The elucidation of exact reaction mechanisms, especially for the purpose of determining the origin of regio- and diastereoselectivity, is essential for furthering the development of substituent divergent reactions. In this study, density functional theory calculations were carried out to elucidate the mechanism and, thereby, the origin of regio- and diastereoselectivity, of the divergent [3 + 2] annulation of an aldimine with alkenes catalyzed by the rare-earth metal scandium (Sc). The reaction mechanism was found to consist of the generation of active species, C(sp³)–H activation, alkene insertion, ring closure, and protonation processes. The alkene insertion process was found to determine the regio- and diastereoselectivity of the reaction. The main role of the additive amine is to lower the positive charge of the Sc atom, thereby weakening and cleaving the Sc–C(sp³) bond, before forming an Sc–C(sp²) bond during the alkene insertion process. These results provide valuable insights into the reactions catalyzed by rare-earth metals.

中文翻译：

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阐明钪催化脂肪族醛亚胺的 β-C(sp3)–H 活化和转化过程中非对映选择性的机制和起源


阐明确切的反应机制，特别是为了确定区域选择性和非对映选择性的起源，对于进一步发展取代基发散反应至关重要。在这项研究中，进行了密度泛函理论计算，以阐明稀土金属钪催化醛亚胺与烯烃的发散[3 + 2]环化的机制，从而阐明区域选择性和非对映选择性的起源。科学）。研究发现反应机理包括活性物质的产生、C(sp ³ )–H 活化、烯烃插入、闭环和质子化过程。发现烯烃插入过程可以确定反应的区域选择性和非对映选择性。添加胺的主要作用是降低Sc原子的正电荷，从而削弱并裂解Sc–C(sp ³ )键，然后形成Sc–C(sp ²