Ozone-mediated nitration of adamantane and derivatives with nitrogen dioxide: selectivity in the hydrogen abstraction by nitrogen trioxide and subsequent coupling of the resulting carbon radicals with nitrogen dioxide1

Abstract

In the presence of ozone at –78 °C, nitrogen dioxide reacts rapidly and selectively with adamantane at a bridgehead position to give the corresponding nitro derivative as the sole major product. The relative reactivity has been determined for a series of 1-substituted adamantanes, which reveals that electron-withdrawing substituents exert a considerable influence on the ease of substitution at the γ-position as well as the distribution of the N- and O-functionalized products. The results may be rationalized in terms of the initial hydrogen abstraction by nitrogen trioxide, followed by rapid trapping of the resulting adamantyl radicals with nitrogen dioxide.