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 or the isocyanide, followed by a rate-determining attack of water on the electron-deficient carbon of the protonated isocyanide. The pK(a) of N-cyclohexylnitrilium ion was determined to be 0.86 +/-0.05. (C) 2001 Elsevier Science Ltd. All rights reserved.