Kinetics and mechanism of acid-catalyzed hydrolysis of cyclohexyl isocyanide and pKa determination of N-cyclohexylnitrilium ion

A novel mechanism for acid-catalyzed hydrolysis of cyclohexyl isocyanide is proposed. It is specific acid/general base catalysis, involving a fast, pre-equilibrium C-protonation of the isocyanide, followed by a rate-determining attack of water on the electron-deficient carbon of the protonated isocyanide. The pKa of N-cyclohexylnitrilium ion was determined to be 0.86±0.05.