Treatment of methyl2-alkynylbenzoates with two to three equivalents of CuX 2 (X = Cl or Br) in refluxing acetonitrile gave isocoumarins 2 in good to excellent chemical yields.
Synthesis of 4-Chloroisocoumarins via Intramolecular Halolactonization of <i>o</i>-Alkynylbenzoates: PhICl<sub>2</sub>-Mediated C–O/C–Cl Bond Formation
作者:Linlin Xing、Yong Zhang、Bing Li、Yunfei Du
DOI:10.1021/acs.orglett.9b00047
日期:2019.4.5
A series of 4-chloroisocoumarins were conveniently synthesized from o-alkynylbenzoates via PhICl2-mediated intramolecular cyclization under metal-free conditions. PhICl2 plays the role of both the oxidant and the chlorine source to enable oxidative C-O bond formation and introduction of the chlorine atom. The utility and practicability of this protocol have been exemplified by virtue of mild reaction conditions, high-yielding products, simplified purification, and gram-scale synthesis.