Effect of Dimethyl Sulfoxide Solvent in the Thermolysis of Alkyl Nitrates Elucidated by the Temperature Dependence of a Kinetic Isotope Effect

Article abstract of DOI:10.1021/jo00342a017

The cyclic, bent TS^* of gas-phase thermolytic decomposition of benzyl nitrate has been compared to the analogous thermal elimination of amine oxides in diglyme solution.The use of Me2SO solvent in amine oxide thermolysis has been shown to alter the TS^* to one which accommodates linear H transfer.Me2SO solvent in the case of benzyl nitrate is now found to afford a nearly quantitative conversion to benzaldehyde.Other alkyl nitrates show a similarly facile reaction to produce good yields of the carbonyl product.However, through measurement of the temperature dependence of k_H/k_D with benzyl-α-d nitrate it is found that the TS^* for decomposition is little altered by comparison with the gas-phase thermolysis reaction.The differences in behavior of the amine oxide and alkyl nitrate reactions in Me2SO and the possible origins of these differences are discussed briefly.