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Chemistry

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Organic Chemistry

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Nucleophilic Substitution and Elimination Reactions of Alkyl Halides

SN1 and SN2 Reaction Factors

Description

Nucleophilic substitution of alkyl halides can follow an SN1 or SN2 pathway. In an SN2 reaction, the nucleophile attacks as the leaving group leaves at the same time. In an SN1 reaction, the substrate first splits to form a carbocation, which is a positively charged intermediate.

The structure of...

Transcript

卤代烷的亲核取代反应可通过SN1或SN2机理进行,具有不同的立体化学结果。

底物的结构、亲核试剂的强度以及溶剂的性质等因素会促进其中一种反应机理而非另一种。

在SN2反应中,亲核试剂在离去基团离开的同时进攻底物。因此,底物上的大位阻取代基会阻碍亲核试剂形成化学键。 Consequently,位阻较小的底物更有利于发生SN2反应。

在SN1反应中,底物首先解离生成碳正离子中间体,该中间体通过诱导效应和超共轭作用得以稳定。

烷基的给电子诱导效应可稳定碳正离子上的电荷。在超共轭效应中,烷基的充满的sp...

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