185566-87-4Relevant academic research and scientific papers
Hypervalent Iodine Oxidations: Structure and Kinetics of the Reactive Intermediates in the Oxidation of Alcohols and 1,2-diols by o-Iodoxybenzoic Acid (IBX) and Dess-Martin Periodinane. A Comparative 1H-NMR Study
Munari, Sergio De,Frigerio, Marco,Santagostino, Marco
, p. 9272 - 9279 (1996)
Alcohols and 1,2-diols oxidation by o-iodoxybenzoic acid (IBX) has been examined by 1H-NMR spectroscopy.Reversible formation of reactive intermediates, iodic esters 5, has been observed, and their structures in DMSO-d6 solution have been defined as 10-I-4 axial alkoxyiodinane oxides by comparison of the chemical shift difference data with those obtained for Dess-Martin periodinane (DMP)-alcoholate and -diolate adducts.The dichotomous behaviour exhibited by IBX and DMP with 1,2-diols can be explained in terms of the different architecture of the reactive intermediates involved in the oxidation.With aliphatic alcohols, kinetic evidences support a two-step reaction mechanism involving a fast pre-equilibrium step leading to 5, followed by a rate-determining disproportionation step.With electronically activated benzyl alcohol, the attainment of pre-equilibrium is largely dependent on initial water concentration as a consequence of a particularly high K2 value.The influence of the alcohol structure on measured equilibrium (Keq) and rate constants (K2) and the effect of water on the overall reaction rate are discussed.
