Poly(N-bromoacrylamide): an efficient and useful catalyst for the protection of carbonyl compounds as dithiolanes, dithianes and oxathiolanes under solvent-free and microwave conditions

Poly(N-bromoacrylamide) (PNBA) was prepared and used as a heterogeneous electrophilic catalyst under solvent-free and microwave conditions for the mild and efficient protection of carbonyl compounds as their dithiolane, dithiane and oxathiolane derivatives with 1,2-ethanedithiol, 1,3-propanedithiol and 2-mercaptoethanol, respectively in good to excellent yields. This method is simple, efficient and straightforward for synthesis of 1,3-oxathiolanes, 1,3-dithiolanes and 1,3-dithianes from carbonyl compounds. The catalyst is recoverable and reusable.