Palladium-Catalyzed Chelation-Assisted Aromatic C鈥揌 Nitration: Regiospecific Synthesis of Nitroarenes Free from the Effect of the Orientation Rules

详细信息    查看全文

• 作者：Wei Zhang ; Shaojie Lou ; Yunkui Liu ; Zhenyuan Xu
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：June 21, 2013
• 年：2013
• 卷：78
• 期：12
• 页码：5932-5948
• 全文大小：1002K
• 年卷期：v.78,no.12(June 21, 2013)
• ISSN：1520-6904

文摘

A palladium-catalyzed chelation-assisted ortho-nitration of aryl C鈥揌 bond is described. A range of azaarenes such as 2-arylquinoxalines, pyridines, quinoline, and pyrazoles were nitrated with excellent chemo- and regioselectivity. Using the O-methyl oximyl group as a removable directing group, the regiospecific synthesis of a variety of o-nitro aryl ketones was achieved starting from aryl ketones via a three-step process involving the Pd-catalyzed ipso-nitration of C鈥揌 bond as a key step. Mechanistic investigations support a silver-mediated radical mechanism involving Pd((II/III) and/or Pd(II/IV) catalytic cycles under oxidizing conditions.