Fujihira Yamato, Hirano Kazuki, Ono Makoto, Mimura Hideyuki, Kagawa Takumi, Sedgwick Daniel M, Fustero Santos, Shibata Norio
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan.
Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan.
J Org Chem. 2021 Apr 16;86(8):5883-5893. doi: 10.1021/acs.joc.1c00298. Epub 2021 Mar 29.
A simple protocol to overcome the explosive pentafluoroethylation of carbonyl compounds by HFC-125 is described. The use of potassium (K) bases with triglyme or tetraglyme as a solvent safely yields the pentafluoroethylation products in good to high yields. The experimental results suggest that an encapsulation of the K cation by glymes as K(glyme) inhibits the contact between the K cation and the reactive anionic pentafluoroethyl counterion, preventing their transformation into KF and explosive tetrafluoroethylene (TFE). The generation of sterically demanding [K(G3)] and [K(G4)] is an effective way as an unstable pentafluoroethyl anion reservoir.
描述了一种克服HFC-125使羰基化合物发生爆炸性五氟乙基化反应的简单方法。使用钾（K）碱并以三甘醇二甲醚或四甘醇二甲醚作为溶剂，能够安全地以良好至高收率得到五氟乙基化产物。实验结果表明，以K(甘醇二甲醚)形式存在的甘醇二甲醚对K阳离子的包裹作用抑制了K阳离子与反应性五氟乙基阴离子抗衡离子之间的接触，从而防止它们转化为KF和爆炸性的四氟乙烯（TFE）。生成空间位阻较大的[K(G3)]和[K(G4)]是作为不稳定五氟乙基阴离子储存库的有效方法。
