Secondary deuterium isotope effects as a sensitive probe for double bond participation. The structure of the cholesteryl cation

Kinetic analysis of the solvolysis of cholesteryl p-toluenesulfonate has led to previously published proposals on the structure of the intermediate resonance-stabilized homoallylic cation. Both symmetrical and unsymmetrical intermediates have been suggested. Results of this study, based on secondary deuterium isotope effect measurements, gave evidence in favor of the unsymmetrical structure. Data on deuterium isotope effects in the solvolysis of cholesteryl tosylates and cholestanyl brosylates in ethanol are given. (JGB)