Rate and Product Studies with 2-Methyl-2-Chloroadamantane under Solvolytic Conditions

Abstract

Reactions of 2-methyl-2-chloroadamantane (1) in a variety of pure and binary solvents have been studied at various temperatures and pressures up to 80 MPa. The sensitivity (m) to changes in solvent ionizing power of the Grunwald-Winstein equation, and the activation volume (<TEX>${\Delta}V^{\ddag}$</TEX>) are calculated from the specific rates. An excellent linear relationship (R = 0.997) for 1, log (k/<TEX>$k_0$</TEX>) = <TEX>$0.80Y_{Cl}$</TEX> + 0.11, and the activation volume, <TEX>${\Delta}V^{\ddag}$</TEX> = -15.2 ~ -10.2 <TEX>$mL{\cdot}mol^{-1}$</TEX> were observed. These values are similar to those for solvolyses of 1-adamantyl halides over the full range of solvents, suggesting that the unimolecular mechanism involving ion pairs is rate-determining. These observations are also compared with those previously reported for the corresponding 1-adamantyl derivatives and chloroformate esters.