Acetic Anhydride-Acetic Acid as a New Dehydrating Agent of Aldoximes for the Preparation of Nitriles: Preparation of 2-Cyanoglycals

Glycals, 1,2-unsatrated carbohydrates, are versatile building blocks for the synthesis of various scaffolds. Despite their potential to serve as suitable precursors in diversity-oriented synthesis, 2-cyanoglycals are less explored in terms of their synthesis and derivatization. Herein, we report a combination of Ac ₂ O and AcOH as new and efficient dehydrating agent of aldoximes for the synthesis of 2-cyanoglycals. In comparison to the conventional dehydrating system of Ac ₂ O-base (such as NaOH, NaOAc and K ₂ CO ₃), the current protocol provides superior yields and faster reaction rates. The scope and limitations of the dehydrating system are investigated.