Chemical Sciences: A Manual for CSIR-UGC National Eligibility Test for Lectureship and JRF/Named Reactions/Reformatsky Reaction

The Reformatsky reaction (sometimes spelled Reformatskii reaction) is an organic reaction which condenses aldehydes (or ketones), 1, with α-halo esters, 2, using a metallic zinc catalyst to form β-hydroxy-esters, 3.ReformatskyReformatsky2 It was discovered by Sergey Nikolaevich Reformatsky. center|500px|The Reformatskii reaction The organozinc reagent, also called a 'Reformatskii enolate', is prepared by treating an alpha-halo ester with zinc dust. Reformatskii enolates are less reactive than lithium enolates or Grignard reagents and hence nucleophilic addition to the ester group does not occur. Some reviews have been published.ShrinerRathke Structure of the reagent The crystal structures of the THF complexes of the Reformatsky reagents tert-butyl bromozincacetate Organometallics 1984 9 3 1403–1407 J. Dekker, P. H. M. Budzelaar, J. Boersma, G. J. M. Van der Kerk, A. J. Spek 10.1021/om00087a015 The nature of the Reformatsky reagent. Crystal structure of (BrZnCH2COO-t-Bu.THF)2 and ethyl bromozincacetate Synthesis 2008 409–412 S. Miki, K. Nakamoto, J. Kawakami, S. Handa, S. Nuwa 10.1055/s-2008-1032023 The First Isolation of Crystalline Ethyl Bromozincacetate, Typical Reformatsky Reagent: Crystal Structure and Convenient Preparation 2008 have been determined. Both form cyclic eight-membered dimers in the solid state, but differ in stereochemistry: the eight-membered ring in the ethyl derviative adopts a tub-shaped conformation and has cis bromo groups and cis THF ligands, whereas in the tert-butyl derviative, the ring is in a chair form and the bromo groups and THF ligands are trans. 200px200px200px200pxethyl bromozincacetate dimertert-butyl bromozincacetate dimer Variations In one variation of the Reformatsky reactionLambert an iodolactone is coupled with an aldehyde with triethylborane in toluene at -78°C. center|400px|Reformatsky reaction Danishefsky variation ref. Lambert 2006 References Bibliography Reformatskii Reformatskii, S., Neue Synthese zweiatomiger einbasischer Säuren aus den Ketonen, Ber. 1887, 20, 1210. doi:10.1002/cber.188702001268 Reformatskii2 Reformatskii, S. J. Russ. Phys. Chem. Soc. 1890, 22, 44. Shriner Shriner, R. L. Org. React. 1942, 1, 1. (Review) Rathke Rathke, M. W. Org. React. 1975, 22, 423. (Review) Lambert Total Synthesis of UCS1025A Tristan H. Lambert and Samuel J. Danishefsky J. Am. Chem. Soc. 2006, 128(2), 426 - 427. (Communication) doi:10.1021/ja0574567 Abstract