Reaction of β-nitrostyrenes with benzene catalyzed by trifluoromethanesulfonic acid. Formation and reaction of n,n-dihydroxyiminium-benzyl dications

Article abstract of DOI:10.1016/S0040-4020(01)89957-9

β-Nitrostyrenes are diprotonated on the nitro group to yield N,N-dihydroxyiminium-benzyl dications in trifluoromethanesulfonic acid. These dications comprise a new class of reagents that can react with benzene. The reaction is dependent on the substituent (H or alkyl group) at the β-position of nitrostyrene: β-nitrostyrene yields diphenylacetophenoneoxime, and β-methyl-β-nitrostyrene yields acetophenoneoxime and triphenylmethane. An essentially common mechanism is suggested to be involved in both reactions. These reactions are novel examples of acidcatalyzed reactions of nitro olefins.