| 词条 | Hoesch reaction |
| 释义 |
| Name = Houben–Hoesch reaction | Type = Coupling reaction | NamedAfter = Josef Houben Kurt Hoesch }} The Hoesch reaction or Houben–Hoesch reaction is an organic reaction in which a nitrile reacts with an arene compound to form an aryl ketone. The reaction is a type of Friedel-Crafts acylation with hydrogen chloride and a Lewis acid catalyst. The synthesis of 2,4,6-Trihydroxyacetophenone (THAP) from phloroglucinol is representative:[1] If two-equivalents are added, 2,4-Diacetylphloroglucinol is the product. An imine is isolated as an intermediate reaction product. The attacking electrophile is possibly[2] a species of the type R-C+=NHCl−. The arene must be electron-rich i.e. phenol or aniline type. A related reaction is the Gattermann reaction in which hydrocyanic acid not a nitrile is used. The reaction is named after Kurt Hoesch[3] and Josef Houben[4] who reported about this new reaction type in respectively 1915 and 1926. MechanismThe mechanism of the reaction involves two steps. The first step is a nucleophilic addition to the nitrile with the aid of a polarizing Lewis acid, forming an imine, which is later hydrolyzed during the aqueous workup to yield the final aryl ketone. See also
References1. ^{{cite journal|last1=Gulati|first1=K. C.|last2=Seth|first2=S. R.|last3=Venkataraman|first3=K.|title=Phloroacetophenone|journal=Organic Syntheses|date=1935|volume=15|page=70|doi=10.15227/orgsyn.015.0070}} 2. ^{{JerryMarch}} 3. ^Eine neue Synthese aromatischer Ketone. I. Darstellung einiger Phenol-ketone Berichte der deutschen chemischen Gesellschaft Volume 48, Issue 1, Date: Januar–Juni 1915, Pages: 1122–1133 Kurt Hoesch {{DOI|10.1002/cber.191504801156}} 4. ^Über die Kern-Kondensation von Phenolen und Phenol-äthern mit Nitrilen zu Phenol- und Phenol-äther-Ketimiden und -Ketonen (I.) Berichte der deutschen chemischen Gesellschaft (A and B Series) Volume 59, Issue 11, Date: 8. Dezember 1926, Pages: 2878–2891 J. Houben {{DOI|10.1002/cber.19260591135}} 2 : Substitution reactions|Name reactions |
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