Side-Chain Nitration of Styrene and Para-Substituted Derivatives with a Combination of Nitrogen Dioxide and Ozone

The side-chain nitration of styrene and four para-substituted derivatives 1 with a combination of nitrogen dioxide and ozone has been investigated as part of our continued effort to define the scope of applicability of this new nitration methodology (kyodai nitration). Styrene and derivatives underwent a smooth addition reaction across the olefinic bond in dichloromethane at −20 °C, affording the corresponding isomeric nitro-nitrato adducts 2 and 3 in excellent combined yield. ¹H-NMR data were collected for all possible nitro-nitrato adducts of styrene and derivatives. The mechanism of the formation of these addition products is discussed in terms of the reversible addition of nitrogen dioxide to form unstable nitroso-nitrates 9 and 10 followed by rapid oxidation of these to the corresponding nitro-nitrates 2 and 3.