Ladenburg吡啶苄基化反应

铜盐作用下，吡啶和苄基卤代物反应得到2位或4位苄基化产物的反应。其他的一些烷基卤代物也可以进行此反应，但产率不高。

反应机理

铜盐催化下的自由基机理

反应操作

Benzylpyridines (3) and (4). Pyr hydrochloride 1 (462 g, 4 mol), CuCl2 (5 g, 37 mmol) and Pyr (60 mL) were treated with benzyl chloride 2 (126.5 g, 115 mL, 1 mol) and refluxed for 12 h. The mixture was distilled until the temperature reached 195 C. The cooled residue was treated with water (200 mL) and 32% HCl (15 mL), stirred until homogeneous and made alkaline with 25% NH4OH.

Extraction with PE: PhH, washing the extract with NH4OH and evaporation afforded a mixture of 3 and 4, bp 123–125 ℃ and 175–190 ℃.