定义Definition
桑德迈尔反应是芳香重氮盐在亚铜盐（CuCl、CuBr、CuCN）催化或参与下，重氮基被 Cl、Br 或 CN 取代并放出氮气的反应，是由苯胺制备卤代芳烃和芳腈的重要方法。
The Sandmeyer reaction replaces the diazonium group of an arenediazonium salt with Cl, Br or CN using copper(I) salts (CuCl, CuBr, CuCN), with loss of nitrogen; it is a key route from anilines to aryl halides and aryl nitriles.
机理Mechanism
Cu(I) 向重氮盐转移一个电子，生成芳基重氮自由基，随即放出 N₂ 得到芳基自由基；芳基自由基从 Cu(II)X 中夺取 X 生成产物并再生 Cu(I)。这是一种自由基-亲核芳香取代（SRN 型）过程，可由联芳烃副产物佐证。
Cu(I) transfers an electron to the diazonium ion; loss of N₂ gives an aryl radical, which abstracts X from Cu(II)X to give the product and regenerate Cu(I). This radical–nucleophilic substitution is supported by biaryl side products.
由来Origin
瑞士化学家特劳戈特·桑德迈尔于 1884 年在尝试制备苯乙炔时偶然发现，用氯化亚铜得到了氯苯。
Discovered by the Swiss chemist Traugott Sandmeyer in 1884 when an attempt to make phenylacetylene with copper(I) chloride gave chlorobenzene instead.
相关反应Related reactions
碘化物不需铜催化（ArN₂⁺ + I⁻ → ArI）；希曼反应用 HBF₄ 制芳基氟；加特曼反应用铜粉代替亚铜盐；水解得酚；次磷酸还原得芳烃（脱氨）。这些反应使重氮盐成为芳环官能团转换的枢纽。
Iodides need no copper (ArN₂⁺ + I⁻ → ArI); the Schiemann reaction gives aryl fluorides via HBF₄; the Gattermann variant uses copper powder; hydrolysis gives phenols; hypophosphorous acid removes the group. Diazonium salts are thus a hub for aromatic functional-group interconversion.
反应Reactions
先在 0–5 °C 重氮化，再加入 CuCl/HCl、CuBr/HBr 或 CuCN/KCN 并温热
Diazotise at 0–5 °C, then add CuCl/HCl, CuBr/HBr or CuCN/KCN and warm
苯胺与亚硝酸生成重氮盐。
The aniline is diazotised with nitrous acid.
Cu(I) 单电子还原重氮盐，放出 N₂ 得芳基自由基。
Single-electron reduction by Cu(I) releases N₂ and an aryl radical.
芳基自由基从 CuX₂ 夺取卤素，再生 Cu(I)。
The aryl radical takes X from CuX₂, regenerating Cu(I).
制备苯甲腈。
Preparation of benzonitrile.
年表Timeline
- 1858
格里斯发现芳香重氮盐
Griess discovers arenediazonium salts
- 1884
桑德迈尔报道铜盐取代
Sandmeyer reports the copper-mediated substitution
- 1927
巴尔茨与希曼报道氟代反应
Balz and Schiemann report the fluorination