Various α-Oxygen Functionalizations of β-Dicarbonyl Compounds Mediated by the Hypervalent Iodine(III) Reagent p-Iodotoluene Difluoride with Different Oxygen-Containing Nucleophiles

Abstract

p-Iodotoluene difluoride (p-Tol-IF₂) has been found to be a general reagent for the effective introduction of various oxygen-containing functionalities including tosyloxy, mesyloxy, acetoxy, phosphoryloxy, methoxy, ethoxy and isopropoxy at the α-position of β-dicarbonyl compounds. These transformations can be readily realized by the use of the combined reagent of p-iodotoluene difluoride and various oxygen-containing nucleophilic compounds such as p-toluenesulfonic acid, methanesulfonic acid, acetic acid, diphenyl phosphate, methanol, ethanol and propan-2-ol under mild conditions, respectively. And, the in situ generated hypervalent iodine(III) species via ligand exchange between p-iodotoluene difluoride and the respective oxygen-containing nucleophiles are believed to be the real oxidizing agents in such transformations.