Nucleophilic participation in the solvolyses of 2‐aryl‐2‐halopropanes and the previously claimed advantage of using Y BnX scales

Contrary to a recent report, the specific rates of solvolyses of five 2‐aryl‐2‐chloropropanes give only marginally (not significantly) better correlations with use of the Y BnCl scale rather than the Y Cl scale. With the use of the extended (two‐term) Grunwald–Winstein equation, some evidence for a weak nucleophilic solvation is obtained, but at a low confidence level. The specific rates of 2‐bromo‐2( p ‐trifluoromethylphenyl)propane solvolysis are significantly better correlated using Y Br (rather than Y BnBr ) values and, indeed, the use of N T values in conjunction with Y Br values leads to an l value of 0·17 ± 0·06 and evidence for a weak nucleophilic participation at a 98·7% confidence level.