Chin. J. Org. Chem. ›› 2009, Vol. 29 ›› Issue (07): 1158-1160. Previous Articles     Next Articles



袁仕祯*,a 刘 瑾a 江国顺b   

  1. (a 安徽建筑工业学院材料与化学工程学院 合肥 230022)
    (b 中国科学技术大学材料科学与工程系 合肥 230026)
  • 收稿日期:2008-10-15 修回日期:2008-12-25 出版日期:2009-07-22 发布日期:2009-07-22
  • 通讯作者: 袁仕祯

Pinacol Coupling of Aldehydes Mediated by Zinc in Aqueous Ammonia Media

Yuan, Shizhen*,a ; Liu, Jin a ; Jiang, Guoshun b   

  1. (a Department of Material and Chemical Engineering, Anhui Institute of Architecture & Industry, Hefei 230022)
    (b Department of Material Science and Engineering, University of Science and Technology of China, Hefei 230026)
  • Received:2008-10-15 Revised:2008-12-25 Online:2009-07-22 Published:2009-07-22
  • Contact: Yuan, Shizhen

The conventional pinacol coupling of carbonyl compounds was carried out by using metals or metal compounds as mediators under condition of anhydrous organic solvents. Previously, it was reported that the pinacol coupling of carbonyl compounds was achieved by zinc under strong base or weak acid condition. Now, a convenient, efficient pinacol coupling of aldehydes mediated by zinc in good yields has been carried out in ammonia water in the presence of a little crown ether. Adding a small amount of crown ether was highly effective to enhance the yields of pinacol from 63% to 84%. Nevertheless, the yield of pinacol was also strongly affected by the steric environment surrounding the carbonyl group. The pinacol coupling of aromatic aldehydes has been achieved with high yields under such a condition. However, the diastereose-lectivities of pinacols were not satisfying. Unfortunately, the ketones and most aliphatic aldehydes appeared inert under the same reaction conditions.

Key words: aqueous media, pinacol coupling, crown ether, zinc