雷福尔马茨基反应（Reformatsky反应、Reformatskii反应）是醛或酮与α-卤代酸酯和锌在惰性溶剂中作用，发生缩合得到β-羟基酸酯的反应。 它首先由俄国化学家雷福尔马茨基发现。

反应机理如下：

溴代酸酯与锌反应得到有机锌试剂中间体，也称“雷福尔马茨基烯醇盐”。然后它与羰基加成，水解，得到产物。溴代酸酯的α-碳上有烷基或芳基均可反应，芳香醛酮也可反应，唯有空间位阻大的底物不反应。有机锌中间体活泼性不强，因此不与酯羰基发生亲核加成，酯基得以保留。

以下是雷福尔马茨基反应的一个例子（碘代内酯与醛和三乙基硼在甲苯中于-78°C反应缩合）：

The Reformatsky reaction (sometimes spelled Reformatskii reaction) is an organic reaction which condenses aldehydes or ketones, with α-halo esters, using a metallic zinc to form β-hydroxy-esters:

The organozinc reagent, also called a 'Reformatsky enolate', is prepared by treating an alpha-halo ester with zinc dust. Reformatsky enolates are less reactive than lithium enolates or Grignard reagents and hence nucleophilic addition to the ester group does not occur. The reaction was discovered by Sergey Nikolaevich Reformatsky.