62572-86-5Relevant articles and documents
Palladium-catalyzed chelation-assisted aromatic C-H nitration: Regiospecific synthesis of nitroarenes free from the effect of the orientation rules
Zhang, Wei,Lou, Shaojie,Liu, Yunkui,Xu, Zhenyuan
, p. 5932 - 5948 (2013/07/26)
A palladium-catalyzed chelation-assisted ortho-nitration of aryl C-H 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-H 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.