Computations Reveal That Electron-Withdrawing Leaving Groups Facilitate Intramolecular Conjugate Displacement Reactions by Negative Hyperconjugation
- Noey, E.L. 2
- Jiménez-Osés, G. 2
- Clive, D.J.L. 1
- Houk, K.N. 2
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1
University of Alberta
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2
University of California Los Angeles
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ISSN: 0022-3263
Año de publicación: 2016
Volumen: 81
Número: 10
Páginas: 4290-4294
Tipo: Artículo
beta Ver similares en nube de resultadosOtras publicaciones en: Journal of Organic Chemistry
Proyectos relacionados
2015/00062/001
Resumen
Intramolecular conjugate displacement (ICD) reactions, developed by the Clive group, form carbocycles and polycyclic amines by intramolecular nucleophilic attack on a Michael acceptor with an allylic leaving group. Quantum mechanical investigations with density functional theory show that ICDs involve a stepwise addition, forming an intermediate stabilized carbanion, followed by elimination. The electron-withdrawing nature of the allylic leaving group facilitates the addition by negative hyperconjugation; the twist-boat conformation of the addition and intermediate is stabilized by this interaction. In the absence of an activating electron-withdrawing group as part of the Michael acceptor, a high energy concerted SN2′ reaction occurs. The reactions of carbon nucleophiles have lower activation energies than those of amines. © 2016 American Chemical Society.