Reactivity and regioselectivity in reactions of methyl and ethyl azides with cyclooctynes: activation strain model and energy decomposition analysis

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• 作者：Felipe de S. Vilhena ; José Walkimar de M. Carneiro
• 关键词：Activation strain model ; Azide ; Cyclooctynes ; DFT ; 1 ; 3 ; dipolar cycloaddition ; Energy decomposition analysis
• 刊名：Journal of Molecular Modeling
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：23
• 期：1
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Computer Applications in Chemistry; Molecular Medicine; Computer Appl. in Life Sciences; Characterization and Evaluation of Materials; Theoretical and Computational Chemistry;
• 出版者：Springer Berlin Heidelberg
• ISSN：0948-5023
• 卷排序：23

文摘

The structures and energies for the Huisgen 1,3-dipolar cycloaddition reactions of methyl and ethyl azides with some cyclooctynes and dibenzocyclooctynes were computed at the B3LYP/6-311++G(d,p) level. The activation strain model (ASM) and quantitative molecular orbital (MO) theory were used to investigate the reactivity and regiochemistry in these reactions. The energy decomposition analysis (EDA) was used to identify the intrinsic electronic factor that lead to the preferential formation of 1,7-regiochemistry products. The reactivity order agrees with formation of more synchronous transition states and lower distortion energies. For the reaction of N₃Met with azacyclooctyne, the 1,7-regiochemistry preference is attributed to a lower FMO gap and a higher contribution of the polarization term of the interaction energy than for the 1,8-transition state. For the reaction with aza-dibenzocyclooctyne, the 1,7-preference is due to a lower strain energy and a more pronounced contribution of the exchange term of the interaction energy.