Nitration of N‐heteroaromatics: The first example of palladium‐catalyzed direct ortho‐nitration of aryl CH bonds is described. A range of azaarenes, such as 2‐arylquinoxalines, pyridines, pyrazoles, and O‐methyl oximes, were nitrated with excellent chemo‐ and regioselectivity (see scheme; DCE=1,2‐dichloroethane). Preliminary mechanistic investigations support a silver‐mediated radical mechanism involving
A novel Pd(OAc)2-NFSI-TFA system was developed for the highly selective ortho-monofluorination directed by diverse aryl-N-heterocyclic directing groups e.g., quinoxaline, pyrazole, benzo[d]oxazole, and pyrazine derivatives. A Pd(II/IV) catalytic cycle was proposed based on the ESI-MS/MS studies.