Highly Convenient Amine-Free Sonogashira Coupling in Air in a Polar Mixed Aqueous Medium by<i>trans</i>- and<i>cis</i>-[(NHC)<sub>2</sub>PdX<sub>2</sub>] (X=Cl, Br) Complexes of<i>N</i>/<i>O</i>-Functionalized N-Heterocyclic Carbenes
作者:Lipika Ray、Samir Barman、Mobin M. Shaikh、Prasenjit Ghosh
DOI:10.1002/chem.200800301
日期:2008.7.28
N/O-functionalized N-heterocyclic carbenes employed in a highly convenient amine-free Sonogashira cross-coupling reaction in air in a polar mixed aqueous medium are reported. Specifically, the trans-[1-benzyl-3-(3,3-dimethyl-2-oxobutyl)imidazol-2-ylidene}(2)PdBr(2)] (3) and cis-[1-benzyl-3-(N-tert-butylacetamido)imidazol-2-ylidene}(2)PdCl(2)] (4) complexes effectively catalyzed the Sonogashira cross-coupling
N / O-官能化的N-杂环卡宾的两个新的反式和顺式-[((NHC)(2)PdX(2)](X = Cl,Br)配合物,用于高度便利的无胺Sonogashira交叉偶联反应中据报道在空气中在极性混合水介质中。具体而言,反式-[1-苄基-3-(3,3-二甲基-2-氧丁基)咪唑-2-亚基}(2)PdBr(2)](3)和顺式[1-苄基- 3-(N-叔丁基乙酰胺基)咪唑-2-亚基}(2)PdCl(2)](4)络合物在混合溶剂(DMF / H(2)O,3:1 v / v)在无胺条件下。有趣的是,这些反式和顺式[(NHC)(2)PdX(2)](X = Cl,Br)配合物,带有两个N-杂环卡宾配体,与现在流行的PEPPSI(吡啶增强的前催化剂)相比,具有更好的活性。准备,稳定和引发)为主题的类似物,反式-[((NHC)Pd(吡啶)X(2)](X = Cl,Br),3a和4a,带有一个N杂环卡宾配体和