Ion-molecule pairs in leaving-group-promoted solvolytic elimination reactions

摘要

Solvolysis of 1-(1-methyl-1-phenylethyl)pyridinium cation (1-P+) in 25 vol 1/00 acetonitrile in water at 60 deg C provides the substitution product 2-hydroxy-2-phenylpropane (1-OH) and the elimination product 2-phenylpropene (3). The fraction of elimination is about half of that obtained with an acetate leaving group of similar basicity. The total rate of reaction is dependent on the basicity of the leaving group, 1-(1-methyl-1-(4-cyanophenyl)ethyl)pyridinium cation (1-P-CN+) reacts 1100 times faster than 1-P+ which corresponds to a Bronsted parameter of β_1g=-0.39.