The ruthenium-catalyzed meta-selective C-H nitration of various azole ring-substituted arenes.

The efficient ruthenium-catalyzed meta-selective C-H nitration of azole ring substituted arenes has been developed. In this work, Ru(CO) was used as the catalyst, AgNO as the nitro source, HPcy·BF as the ligand, pivalic acid as the additive, and DCE as the solvent, and a wide spectrum of arenes bearing thiazole, pyrazolyl or removable oxazoline directing groups were tolerated in this meta-selective C-H nitration, affording the nitrated products in moderate to good yields. Moreover, this study reveals a gentler and environmentally friendly way to access meta-nitration arenes compared to the traditional process.