Percarbamate de t-butyle et ses dérivés N-alkylés, N,N-dialkylés et N-azacyclaniques: préparation et thermolyse en solution

Several tert-butyl percarbamates have been prepared by the reaction of amines with tert-butyl imidazolylpercarboxylate. The thermal decomposition of these peresters in solution led to the characteristic products of homolytic processes. The kinetic study of the thermolysis has been performed by Differential Scanning Microcalorimetry. It showed the influence of the nitrogen atom substitution on the percarbamate stability. The kinetic study of the decompositions of percarbamates derived from cyclic amines showed an important effect of the cycle size on the rate constant. Very different transition state levels are responsible for this phenomenon. A stereoelectronic origin—from the overlapping of the p-orbital of the nitrogen atom and the π bond of the carboxyl—has been advanced to account for this result.