% D in 9Zfrom lib= kc where R= kdko for deprotonation of chlorolium ion 13; kc= rate constant for 12-13;= rate constant for 12-92, ka= rate constant for 12= kM/b, which is the isotope effect for deprotonation of vinyl cation 12. To solve these equations, it is necessary to assume a value for either R or fH/pO. Once the equatlon is solved, the fraction of 9 Z formed from chioroiium ion is given by 1/(1 t fH).