A series of 4′-substituted anti-7-benzonorbornenyl p-bromobenzenesulfonates was prepared and the acetolysis of these sulfonates proceeds with retention of configuration. The relative rates of CH3O, CH3, H, Cl, Br, and NO2 derivatives at 77.60° were 53.7, 5.7, 1, 0.045, 0.030, and 1.39 × 10-4, respectively. The data indicate major participation by the aromatic ring, facilitating acetolysis. The
... [Show full abstract] rate data are not correlated by the Hammett relationship, log (k/k0) = pσ, or by the modified Hammett relationship, log (k/k0) = ρσ+. They are correlated with good precision by (σ+ + σ) or by (σρ+ + σm+), yielding straight lines with ρ = -2.40 or -2.55. The implications of this correlation in terms of the precise nature of the participation in the transition state for the acetolysis are discussed.
