Nitration of Strongly Deactivated Aromatics with Superacidic Mixed Nitric-Triflatoboric Acid (HNO3/2CF3SO3H-B(O3SCF3)3)
The nitration of various deactivated arenes (including methanesulfonyl-, nitro-, and polyhalobenzenes) was carried out in good yield with mixed nitric-triflatoboric superacid.For example pentafluorobenzene gave pentafluoronitrobenzene in 99percent yield, nitrobenzene to m-dinitrobenzene in 92percent selectivity with 85percent overall yield, and methyl phenyl sulfone gave only the m-nitro isomer in 78percent isolated yield.Thus the new nitrating system gives high regioselectivity and yields under generally mild reaction conditions.The reagent system is compatible with many functional groups of arenes.
Olah, George A.,Orlinkov, Alexander,Oxyzoglou, Alexandros B.,Prakash, G. k. Surya