Introduction of N-sulfonic acid poly(4-vinylpyridinum) chloride as an efficient and reusable catalyst for the chemoselective 1,1-diacetate protection and deprotection of aldehydes

N-sulfonic acid poly(4-vinylpyridinium) chloride is easily prepared by the reaction of poly(4-vinylpyridine) with neat chlorosulfonic acid. This reagent can be used as an efficient catalyst for the preparation of 1,1-diacetates at room temperature and neat condition. Deprotection of the resulting 1,1-diacetates can also be achieved using the same catalyst in methanol. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be reused and recovered for several times.

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► Synthesis of N-sulfonic acid poly(4-vinylpyridinum) chloride (NSPVPC).
► Characterization and application of NSPVPC for the acylation of aldehydes and deprotection of the obtained 1,1-diacetates.
► Catalysis under solvent-free conditions.
► Heterogeneous catalysis and recyclability of the catalyst.