Zhou Chengxiang, Larock Richard C
Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
J Org Chem. 2006 Apr 28;71(9):3551-8. doi: 10.1021/jo060220g.
The unprecedented palladium-catalyzed C-H addition of arenes to nitriles provides moderate to excellent yields of aryl ketones or the corresponding hindered imines. The addition of a small amount of DMSO increases the yields dramatically. Both intermolecular and intramolecular reactions are successful, although the intramolecular reactions tend to be more sluggish. This novel chemistry is believed to involve palladium-catalyzed C-H activation of the arene by electrophilic aromatic substitution, followed by the unusual carbopalladation of a nitrile. Similar reactions have been successfully developed employing arylboronic acids and nitriles. A concise route to xanthones starting from cheap starting materials has been developed employing this synthetic protocol.
前所未有的钯催化芳烃与腈的C-H加成反应能以中等至优异的产率得到芳基酮或相应的受阻亚胺。加入少量二甲基亚砜可显著提高产率。分子间和分子内反应均成功，不过分子内反应往往较为缓慢。据信这种新化学过程涉及通过亲电芳香取代实现钯催化芳烃的C-H活化，随后是腈的异常碳钯化反应。使用芳基硼酸和腈也成功开发了类似反应。利用该合成方案已开发出一条从廉价起始原料出发合成呫吨酮的简洁路线。
