Classical carbonium ions. Part VI. Rearrangement during acetolysis of some 2-adamantyl derivatives

Abstract

Deamination of 2-aminoadamantane in acetic acid gives 2-adamantyl acetate but no detectable 1-adamantyl acetate; a 4→2 hydride shift is also undetectable. Unexpectedly the products include substantial amounts of skeletally rearranged products which are much less stable than adamantane derivatives. Acetolysis of 2-adamantyl toluene-p-sulphonate also gives, in smaller yield, a skeletally rearranged acetate. The significance of these highly endothermic alkyl shifts is discussed, and reasons are advanced for postulating weak σ-participation in the 2-adamantyl cation.