An Oxidant-Free Single-Step Synthesis of Tetra- or Disubstituted Symmetrical Pyridine Derivatives by a Hf(OTf)4-Catalyzed Annulation
作者:Takeo Konakahara、Toshiaki Sasada、Fuminori Kobayashi、Masato Moriuchi、Norio Sakai
DOI:10.1055/s-0030-1260978
日期:2011.9
Hf(OTf)4-catalyzed unprecedented annulation of an enamine with triethyl orthoformate leading to the preparation of tetrasubstituted symmetrical pyridine derivatives without an oxidant is described. This method accommodated the single-step synthesis of a disubstituted symmetrical pyridine using an acetophenone derivative, triethyl orthoformate, and ammonium acetate (NH4OAc).
描述了 Hf(OTf)4 催化的烯胺与原甲酸三乙酯的前所未有的环化,导致在没有氧化剂的情况下制备四取代的对称吡啶衍生物。该方法适用于使用苯乙酮衍生物、原甲酸三乙酯和乙酸铵 (NH4OAc) 一步合成双取代对称吡啶。