Oxidation of azides by the HOF.CH3CN: a novel synthesis of nitro compounds

The HOF.CH3CN complex, readily prepared by passing F2 through aqueous acetonitrile, is an exceptionally efficient oxygen transfer agent. It is unique in its capacity to oxidize various azides into the corresponding nitro derivatives. This method requires short reactions times and room temperature or below, and the desired nitro compounds were usually isolated in very good yields. The respective nitroso derivatives are believed to be the intermediates in this reaction. Functional groups such as aromatic rings, ketones, nitriles, halides, alcohols, and esters are tolerated. Sulfides react with HOF.CH3CN usually at the same rate as azides. Amines and olefins, however, react faster, so they have to be protected first. Nitro derivatives with various oxygen isotopes can be made using the labeled H18OF.CH3CN. In the case of chiral azides the stereochemistry around the nitrogen-bonded carbons is retained.