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m Typo/general fixing, replaced: a electron-withdrawing group → an electron-withdrawing group using AWB (8853)
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In [[organic chemistry]], the '''Vicarious nucleophilic substitution''' is a special type of [[nucleophilic aromatic substitution]] in which a [[nucleophile]] replaces a hydrogen atom on the aromatic ring and not [[leaving group]]s such as [[halogen]] substituents which are ordinarily encountered in S<sub>N</sub>Ar. This reaction type was reviewed in 1987 by [[Polish people|Polish]] chemists [[Mieczysław Mąkosza]] and [[Jerzy Winiarski]].<ref>''Vicarious nucleophilic substitution of hydrogen.'' Mieczysław Mąkosza and Jerzy Winiarski. [[Acc. Chem. Res.]]; '''1987'''; 20(8) pp 282 - 289; {{DOI|10.1021/ar00140a003}}</ref><ref>''Synthesis of heterocyclic compounds via vicarious nucleophilic substitution of hydrogen'' Mieczysław Mąkosza [[Pure & Appl. Chem.]], Vol. 69, No. 3, pp. 559-564, '''1997''' [http://www.iupac.org/publications/pac/1997/pdf/6903x0559.pdf Article link].</ref> |
In [[organic chemistry]], the '''Vicarious nucleophilic substitution''' is a special type of [[nucleophilic aromatic substitution]] in which a [[nucleophile]] replaces a hydrogen atom on the aromatic ring and not [[leaving group]]s such as [[halogen]] substituents which are ordinarily encountered in S<sub>N</sub>Ar. This reaction type was reviewed in 1987 by [[Polish people|Polish]] chemists [[Mieczysław Mąkosza]] and [[Jerzy Winiarski]].<ref>''Vicarious nucleophilic substitution of hydrogen.'' Mieczysław Mąkosza and Jerzy Winiarski. [[Acc. Chem. Res.]]; '''1987'''; 20(8) pp 282 - 289; {{DOI|10.1021/ar00140a003}}</ref><ref>''Synthesis of heterocyclic compounds via vicarious nucleophilic substitution of hydrogen'' Mieczysław Mąkosza [[Pure & Appl. Chem.]], Vol. 69, No. 3, pp. 559-564, '''1997''' [http://www.iupac.org/publications/pac/1997/pdf/6903x0559.pdf Article link].</ref> |
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It is typically encountered with [[nitrobenzene|nitroarenes]] and especially with |
It is typically encountered with [[nitrobenzene|nitroarenes]] and especially with charlotte nucleophiles, resulting in alkylated arenes: the new substituent can take the [[Arene substitution patterns|''ortho'' or ''para'']] positions, reversing the selectivity for the ''meta'' position that is usually observed with such compounds under [[electrophilic aromatic substitution|electrophilic substitution]]. Carbon nucleophiles carry an [[electron-withdrawing group]] and a [[leaving group]]: the nucleophile attacks the aromatic ring, and excess base can [[Elimination reaction|eliminate]] to form an exocyclic double bond which is successively protonated under acidic condition, restoring [[aromaticity]]. |
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:[[Image:VicariousNucleophilicSubstitution.png|400px|Vicarious nucleophilic substitution]] |
:[[Image:VicariousNucleophilicSubstitution.png|400px|Vicarious nucleophilic substitution]] |
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Inorganic chemistry, the Vicarious nucleophilic substitution is a special type of nucleophilic aromatic substitution in which a nucleophile replaces a hydrogen atom on the aromatic ring and not leaving groups such as halogen substituents which are ordinarily encountered in SNAr. This reaction type was reviewed in 1987 by Polish chemists Mieczysław Mąkosza and Jerzy Winiarski.[1][2]
It is typically encountered with nitroarenes and especially with charlotte nucleophiles, resulting in alkylated arenes: the new substituent can take the orthoorpara positions, reversing the selectivity for the meta position that is usually observed with such compounds under electrophilic substitution. Carbon nucleophiles carry an electron-withdrawing group and a leaving group: the nucleophile attacks the aromatic ring, and excess base can eliminate to form an exocyclic double bond which is successively protonated under acidic condition, restoring aromaticity.
