Condition-Controlled O -Acylation and N-O Bond Reduction of Hydroximic Acids with Thioacetic Acid.

Condition-dependent transformations between hydroximic acids and thioacetic acid were achieved. Using NH 4 HCO 3 in the ethanol solvent, efficient N-O bond cleavage of hydroxamic acids occurred to afford primary amides with high functional group compatibility. The reaction was switched to O -acylation when NEt 3 and H 2 O were used as the base and solvent, respectively. These facile transformations could be scaled up to the gram level smoothly. Preliminary mechanistic studies suggested that the N-O bond cleavage involves a cascade process of acylation/reduction.