Synthesis and chemistry of α-iodoperfluoroacid esters
摘要:
The title compounds have been synthesized by irradiation of acetonitrile solutions of perfluoroacid esters and diesters containing tetrabutylammonium iodide. They are versatile synthetic intermediates from which ketenes, Reformatsky adducts, alpha,beta-unsaturated esters and alpha-hydroesters can be prepared. (c) 2006 Elsevier B.V. All rights reserved.
Radical chain reaction of difluoroiodoacetate with olefins catalyzed by copper provided atom-transfer products in good yields.
由铜催化的二氟碘乙酸酯与烯烃的自由基链反应以良好的产率提供了原子转移产物。
A novel and practical method for the preparation of α,α-difluoro functionalized esters
作者:Zhen-Yu Yang、Donald J. Burton
DOI:10.1039/c39920000233
日期:——
α,α-Difluoro functionalized esters can be readily prepared in good yields from the reaction of iododifluoroacetates with alkenes and zinc in the presence of catalytic amounts of nickel dichloride hexahydrate.
organofluorine compounds. Although the preparation of several β-fluoroalkyl-acrylates is known, a general and straightforward lab-scale methodology for the preparation of multigram amounts of these compounds from fluoroacetic esters is not available, and the related chemistry has not been investigated in detail. We now describe an optimized three-step protocol relying on: (1) Claisen-type condensation of fluoroacetic
β-氟烷基丙烯酸酯是有机氟化合物合成的重要组成部分。尽管已知几种β-氟代烷基丙烯酸酯的制备方法,但尚无用于从氟代乙酸酯制备数克这些化合物的通用且直接的实验室规模方法,并且尚未对相关化学方法进行详细研究。现在,我们基于以下内容描述一种优化的三步协议:(1)使用LDA作为碱,将氟乙酸酯与乙酸乙酯进行Claisen型缩合;(2)以甲苯或苯为溶剂,用NaBH 4还原所得的γ-氟-β-酮酯。(3)P 2 O 5促进中间体γ-氟-β-羟基酯的脱水。该方法可提供仅包含氟原子(CF 3,CHF 2,C 2 F 5)的目标化合物的制备有用的产率,而无法以分析纯的形式获得γ-卤代二氟甲基(CClF 2,CBrF 2,CIF 2)丙烯酸酯从脱水步骤中形成。
Copper catalyzed addition reaction of iododifluoroacetates to olefins
作者:Zhen-Yu Yang、Donald J. Burton
DOI:10.1016/s0022-1139(00)82877-8
日期:1989.12
The addition of iododifluoroacetates to alkenes is catalyzed by copper powder (10-20 mol %) at 50° to 60°C. The reaction can be carried out neat or in hexane or benzene as solvent. Both terminal and internal alkenes gave good yields (65-83%). Reduction of the adduct with tributyltin hydride provides the α, α-difluoroacetate.
(Methyl Difluoroacetate)copper Reagent. Remarkable Solvent Effect on the<sup>19</sup>F-NMR Spectrum, Stability and Reactivity
作者:Osamu Kitagawa、Takeo Taguchi、Yoshiro Kobayashi
DOI:10.1246/cl.1989.389
日期:1989.3
The 19F-NMR spectrum, thermal stability and reactivity of (methyl difluoroacetate)copper reagent were found to differ remarkably depending on the solvent (DMSO, DMF, or HMPA) used. With allylic bromide or alkynyl halide a crucial solvent effect for the coupling reactions was observed.