Nickel-Catalyzed Regioselective C–H Bond Mono- and Bis-Nitration of Aryloxazolines with tert-Butyl Nitrite as Nitro Source

An efficient and regioselective nickel-catalyzed remote C–H nitration of 2-aryloxazoline amides using the non-corrosive tert-butyl nitrite (TBN) as nitro source has been developed. The protocol makes use of inexpensive nickel salts as catalysts and delivers the corresponding products in excellent yields. Notably, bis-nitration products were obtained by simply increasing the amount of tert-butyl nitrite. This reaction proceeds in air and features excellent functional group compatibility, broad substrate scope and is suitable for gram-scale synthesis. (Figure presented.).