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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. An example is the synthesis of 1-(2,4,6-trihydroxyphenyl)ethanone from phloroglucinol:〔Organic Syntheses, Coll. Vol. 2, p.522 (1943); Vol. 15, p.70 (1935). http://www.orgsynth.org/orgsyn/pdfs/CV2P0522.pdf〕 : A ketimine is isolated as an intermediate reaction product. The attacking electrophile is possibly 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〔''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 〕 and Josef Houben〔''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 〕 who reported about this new reaction type in respectively 1915 and 1926. ==Mechanism== The 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 latter hydrolyzed during the aqueous workup to yield the final aryl ketone. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hoesch reaction」の詳細全文を読む スポンサード リンク
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