Horner-Wadsworth-Emmons Modification for Ramirez <i>gem-</i>Dibromoolefination of Aldehydes and Ketones Using P(O<i>i</i>-Pr)<sub>3</sub>
作者:Mark Lautens、Yuan-Qing Fang、Olga Lifchits
DOI:10.1055/s-2008-1032045
日期:2008.2
A simple procedure for the use of triisopropylphosphite in the Ramirez olefination is described. This reagent is equally or more reactive than PPh3 toward aldehydes and ketones in the gem-dibromoolefination of aldehydes and ketones. Under the reaction conditions, an α-bromoketone gave a novel tribromomethyl-substituted oxirane product in good yield. The substrate-dependent nature of this reaction suggests that this Horner-Wadsworth-Emmons equivalent of the Ramirez gem-dibromoolefination reaction proceeds through an ionic mechanism.
介绍了在Ramirez烯化反应中使用三异丙基亚磷酸酯的一个简单程序。在醛和酮的偕二溴烯化反应中,该试剂对醛和酮的反应性等同或高于三苯基膦。在反应条件下,α-溴酮以良好产率生成了一种新型三溴甲基取代的环氧乙烷产物。这一反应的底物依赖性质表明,Ramirez偕二溴烯化反应的Horner-Wadsworth-Emmons等效过程是通过离子机制进行的。