A zinc(II)-catalyzed single-step protocol for the Beckmann rearrangement using hydroxylamine-O-sulfonic acid (HOSA) as the nitrogen source in water was developed. This direct method efficiently produces secondary amides under open atmosphere in a pure form after basic aqueous workup. It is environmentally benign and operationally simple.
Key words
zinc(II) chloride - hydroxylamine-
O-sulfonic acid (HOSA) - ketones - Beckmann rearrangement - amides