An Asymmetric SN2 Dynamic Kinetic Resolution
| Autor: | Nomaan M. Rezayee, Gabriel J. Reyes-Rodríguez, Johannes N. Lamhauge, Kendall N. Houk, Chenxi Lu, Sif T. Linde, Karl Anker Jørgensen, Valdemar J. Enemærke |
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| Rok vydání: | 2021 |
| Předmět: |
Substitution reaction
Chemistry General Chemistry 010402 general chemistry 01 natural sciences Biochemistry Catalysis 0104 chemical sciences law.invention Kinetic resolution Stereocenter Colloid and Surface Chemistry Nucleophile law Computational chemistry SN2 reaction Racemic mixture Stereoselectivity Walden inversion |
| Zdroj: | Rezayee, N M, Enemærke, V J, Linde, S T, Lamhauge, J N, Reyes-Rodríguez, G J, Jørgensen, K A, Lu, C & Houk, K N 2021, ' An Asymmetric S N 2 Dynamic Kinetic Resolution ', Journal of the American Chemical Society, vol. 143, no. 19, pp. 7509-7520 . https://doi.org/10.1021/jacs.1c02193 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.1c02193 |
| Popis: | The SN2 reaction exhibits the classic Walden inversion, indicative of the stereospecific backside attack of the nucleophile on the stereogenic center. Observation of the inversion of the stereocenter provides evidence for an SN2-type displacement. However, this maxim is contingent on substitution proceeding on a discrete stereocenter. Here we report an SN2 reaction that leads to enantioenrichment of product despite starting from a racemic mixture of starting material. The enantioconvergent reaction proceeds through a dynamic Walden cycle, involving an equilibrating mixture of enantiomers, initiated by a chiral aminocatalyst and terminated by a stereoselective SN2 reaction at a tertiary carbon to provide a quaternary carbon stereocenter. A combination of computational, kinetic, and empirical studies elucidates the multifaceted role of the chiral organocatalyst to provide a model example of the Curtin-Hammett principle. These examples challenge the notion of enantioenriched products exclusively arising from predefined stereocenters when operating through an SN2 mechanism. Based on these principles, examples are included to highlight the generality of the mechanism. We anticipate the asymmetric SN2 dynamic kinetic resolution to be used for a variety of future reactions. |
| Databáze: | OpenAIRE |
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