Ammoxidation of Unprotected Glycosides: A One-Pot Conversion of Alcohols to Nitriles

Functionalized carbohydrates are important in various fields, but protection-free selective functionalization often remains challenging. We demonstrate that the primary hydroxy group in minimally protected carbohydrates can be directly converted into a nitrile group with TEMPO, PIDA and ammonium acetate. Both nitrile hexopyranoses and nitrile pentofuranoses are obtained and subsequent derivatizations of the nitrile group to other versatile functional groups are demonstrated. Combined evidence from literature and in-situ reaction progress monitoring with Raman spectroscopy led to the proposal that an iminoiodinane derived from PIDA plays an important role in the mechanism of the ammoxidation.