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Acyloin condensation is a reductive coupling of two carboxylic esters using metallic sodium to yield an α-hydroxyketone, also known as an acyloin.〔Bloomfield, J. J.; Owsley, D. C.; Nelke, J. M. ''Org. React.'' 1976, ''23''.〕 The reaction is most successful when ''R'' is aliphatic and inert. The reaction is performed in aprotic solvents with a high boiling point, such as benzene and toluene. The use of protic solvents results in the Bouveault-Blanc reduction of the separate esters rather than condensation. Depending on ring size and steric properties, but independent from high dilution, the acyloin condensation of diesters favours intramolecular cyclisation over intermolecular polymerisation. == Mechanism== The mechanism consists of four steps: :(1) Oxidative ionization of two sodium atoms on the double bond of two ester molecules. :(2) Free radical coupling between two molecules of the homolytic ester derivative (A Wurtz type coupling). Alkoxy-eliminations in both sides occur, producing a 1,2-diketone. :(3) Oxidative ionization of two sodium atoms on both diketone double bonds. The sodium enodiolate is formed. :(4) Neutralization with water to form the enodiol, which tautomerizes to acyloin.〔( Acyloin condensation )〕 : 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「acyloin condensation」の詳細全文を読む スポンサード リンク
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