The Reformatsky reaction (sometimes transliterated as Reformatskii reaction) is an organic reaction which condenses aldehydes or ketones with α-halo esters using 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.
Some reviews have been published.
In addition to aldehydes and ketones, it has also been shown that the Reformatsky enolate is able to react with acid chlorides,  imines, nitriles (see Blaise reaction), and nitrones. Moreover, metals other than zinc have also been used, including magnesium, iron, cobalt, nickel, germanium, cadmium, indium, barium, and cerium. Additionally, metal salts are also applicable in place of metals, notably samarium(II) iodide, chromium(II) chloride, titanium(II) chloride, cerium(III) halides such as cerium(III) iodide, and titanocene(III) chloride.