Metal-free, room temperature, acid-K(2)S(2)O(8) mediated method for the nitration of olefins: an easy approach for the synthesis of nitroolefins

Here, we have developed a simple, room temperature method for the nitration of olefins by using inexpensive sodium nitrite as a source of nitro groups in the presence of trifluoroacetic acid (TFA) and potassium persulfate (K(2)S(2)O(8)) under an open atmosphere. Styrenes and mono-substituted olefins give stereo-selective corresponding E-nitroolefins under optimized conditions, however, 1,1-bisubstituted olefins give a mixture of E- and Z-nitroolefins. The optimized conditions work well with electron-donating, electron-withdrawing, un-substituted and heterocyclic styrenes and mono-substituted olefins and give corresponding nitroolefins with good to excellent yields.