Theoretical Studies on the Gas-Phase Nucleophilic Aromatic Substitution Reaction

The gas-phase nucleophilic substitution reaction of pentafluoroanisole with $OH^-$ and ${NH_2}^-$ nucleophiles have been studied theoretically using the AM1 method. Three reaction channels, $S_N2$, IPSO and $S_NAr$ (scheme 1), are all very exothermic so that all are accessible despite the varying ce...

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Bibliographic Details
Published inBulletin of the Korean Chemical Society Vol. 12; no. 6; pp. 658 - 661
Main Authors Lee, Ik-Choon, Park, Hyoung-Yeon, Bon-Su Lee
Format Journal Article
LanguageKorean
Published 1991
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Summary:The gas-phase nucleophilic substitution reaction of pentafluoroanisole with $OH^-$ and ${NH_2}^-$ nucleophiles have been studied theoretically using the AM1 method. Three reaction channels, $S_N2$, IPSO and $S_NAr$ (scheme 1), are all very exothermic so that all are accessible despite the varying central energy barriers which are much lower than the reactants level. In the IPSO and $S_NAr$ channels, the reactants form directly a stable ,${\sigma}$-anion complex which proceeds to form a proton transfer complex via a transition barrier corresponding to a loose ${\pi}$-type complex with the F-(or ${OCH_3}^-$) leaving group. Due to a greater number of probable reaction sites available for $S_NAr$ compared to the other two processes, the $S_NAr$ channel is favored as experimentally observed.
Bibliography:KISTI1.1003/JNL.JAKO199113464456954
ISSN:0253-2964
1229-5949