Polar Effects. X. Polar Substituent Effects in the Solvolysis of 3‐Substituted 1‐Adamantyl Bromides and Toluenesulfonates

Abstract

Abstract The rate constants for 3‐substituted adamantyl p ‐toluenesulfonates 3a ‐ 3k in ethanol/water 80:20 correlate well with the respective inductive substituent constants σ . The reaction constant ρ for the toluenesulfonates 3 is 10% larger than for the corresponding bromides 2 , indicating somewhat more charge separation in the activation of the toluenesulfonates. Evidence is presented that stabilization of the resultant 1‐adamantyl cations by induction involves graded 1,3‐bridging, which is favored when the substituent is an electrofugal group, and that stabilization by n‐electron donors involves C, C‐hyperconjugation. Rate ratios for the toluenesulfonates 3 and the bromides 1 exceed 10 3 and are almost independent of the 3‐substituents. The implications of this are discussed in the light of current hypotheses.