Chemoselective synthesis of 1,1-diacetates (acylals) using 1,1 ‐butylenebispyridinium hydrogen sulfate as a new, halogen‐free and environmental-friendly catalyst under solvent-free conditions

In this study, an efficient and simple procedure is reported for the chemoselctive acetylation of various aldehydes (aromatic and aliphatic) with acetic anhydride by 1,1 ‐butylenebispyridinium hydrogen sulfate (Bbpy)(HSO4)2 as a green and halogen-free catalyst under solvent-free conditions at room temperature. The selective conversion of the aldehydes was observed in the presence of ketones, and the deprotection of 1,1-diacetates has also been achieved using (Bbpy)(HSO4)2 in water as a green solvent in reflux conditions. This procedure has valuable advantages including short reaction times, simple workup, high yields of products, absence of solvent, and use of commercially available and non-toxic reagents.