scheme for the synthesis of 3-substituted functionalized flavones was developed. The reaction of flavanone and glyoxylic acid in ethanol in the presence of the catalytic amount of sulphuric acid at reflux temperature for 2–3 h yielded good to excellent functionalized flavones. As per present scenario for the synthesis of different substituted flavones, this method represents mild reaction conditions, low-cost
N-Heterocyclic Carbene/Brønsted Base Cascade Catalysis: Base-Controlled Selective Synthesis of Multifunctional Benzofuran-3-ones or Flavone Derivatives from the Reaction of 3-(2-Formylphenoxy)propenoates with Imines
作者:Yuan Zhao、Zi-Tian Wang、Ying Cheng
DOI:10.1002/adsc.201400331
日期:2014.8.11
AbstractThe N‐heterocyclic carbene/Brønsted base cascade catalysis in the reaction of 3‐(2‐formylphenoxy)propenoates with N‐Boc‐arylimines has been studied. Both multifunctional benzofuran‐3‐ones and benzopyran‐4‐ones (flavone derivatives) were selectively synthesized in good yields simply by regulating the loading of the base catalyst.magnified image