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The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts.〔 〕〔 〕〔 〕 It is named after the Swiss chemist Traugott Sandmeyer. The reaction is a method for substitution of an aromatic amino group via preparation of its diazonium salt followed by its displacement with a nucleophile, often catalyzed by copper(I) salts. The nucleophile can include halide anions, cyanide, thiols, water, and others. The reaction does not proceed well with the fluoride anion, but fluorination can be carried out using tetrafluoroborate anions (Balz–Schiemann reaction). ==Reaction mechanism== The nitrous acid is usually prepared ''in situ'' from sodium nitrite and an acid. Following a 2nd protonation step, one equivalent of water is lost to form nitrogen monoxide cation i.e. the "Nitronium ion" electrophile. : An aromatic (or heterocyclic) amine quickly reacts with a nitrite to form an aryl diazonium salt, which decomposes in the presence of copper(I) salts, such as CuCl, to form the desired aryl halide. It is carried out at the temperature of 25-30 °C. The reaction is a radical-nucleophilic aromatic substitution. Several improvements have been made to the standard procedures.〔Suzuki, N. ''et al.'' ''Perkins Trans. I'' 1987, 645.〕 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「Sandmeyer reaction」の詳細全文を読む スポンサード リンク
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