Reactivity patterns of N-methylbenzhydroxamates. I. Studies of methyl transfer between N-methylbenzhydroxamates and arenesulfonates

Abstract

The rates of methyl transfer between benzohydroxamates and sulfonates show large βnuc values (ca. 0.8) indicating much charge transfer to the C atom, similar to the results of N,N-dialkylaminofluorene anions. A small α effect shows that even in methyl substrates, with certain leaving groups, the effect is displayed. Investigation of the β1g shows that from the leaving group side of the reaction it is a normal SN2 reaction. Correlation of the reactivity with computed gas phase ionization potentials shows that desolvation of anions is probably not important. These results suggest an α-effect model that explains the larger size of the effect at carbonyl groups in terms of greater solvation of the charge transferred to the O atom. Key words: α effect, Brønsted plot, ionization potentials, cyclic voltammetry, β1g, βnuc, AMl, [Formula: see text]