PdCl2(PPh3)2 in a mixture of water and poly(ethylene glycol) (PEG-2000) is shown to be an extremely active catalyst for the carbonylative Sonogashira coupling reaction of aryl iodides with terminal alkynes. The reaction can be conducted under an atmospheric pressure of carbon monoxide at 25 °C with Et3N as a base, yielding a variety of alkynyl ketones in good to excellent yields. Application of this synthetic method to prepare flavones from o-iodophenol and terminal alkynes was also achieved. The isolation of the products is readily achieved by extraction with diethyl ether, and the PdCl2(PPh3)2/PEG-2000/H2O system can be easily recycled and reused six times without any loss of catalytic activity.
在
水和聚
乙烯醇(P
EG-2000)的混合物中,PdCl2(PPh3)2被证明是一种极为活跃的催化剂,可以催化芳基
碘与末端
炔烃的羰基化索诺加希拉偶合反应。该反应可以在25 °C、用
三乙胺作为碱的情况下,在常压的
二氧化碳气氛下进行,结果得到多种炔基酮,产率良好至优异。采用这种合成方法还能成功将邻
碘苯酚与末端
炔烃转化为
黄酮。产品的分离通过二
乙醚提取即可轻松实现,PdCl2(PPh3)2/P
EG-2000/
H2O体系可轻松回收并重复使用六次,且没有任何催化活性损失。