The thermolysis of 18O labelled t-butyl NN-dimethyl carbamate and its possible bearing on the course of thermal β-elimination reaction mechanisms

Abstract

The absence of randomisation of the oxygen label in the unreacted ¹⁸O carbamate, after subjecting NN-dimethyl carbamate to thermolysis under noncatalytic conditions which effect ca. 60%β-elimination, is evidence against an ion-pair intermediate intervening in even the lowest activation gas-phase ester elimination processes; an unsymmetrical, concerted transition state of bond breaking and making is proposed.