Classical carbonium ions. Part VIII. Deamination of cis- and trans-4-t-butylcyclohexylamines

Abstract

Using several different procedures cis- and trans-4-t-butylcyclohexylamines have been deaminated in acetic acid containing potassium acetate. Particular importance is attached to the acetolysis of the N-butyryl-N-nitroso derivatives in which the internal nucleophile X(butyrate) and the external nucleophile Y (acetate) give product mixtures which were separately analysed into unrearranged and rearranged esters of retained and inverted configurations. The product analyses define the effective intermediate in the deamination process as an ion-pair comprising a carbonium ion well separated from a hydrogen-bonded, complex anion [X ⋯ H ⋯ Y]^–. These ion-pairs are short lived compared with the rate of stereomutation; diazonium ions, if formed at all, live too briefly to have observable properties. The products of acetolysis of 1-diazo-4-t-butylcyclohexane are also reported and compared with those of the deamination reactions.