A rapid and green synthesis of 1,1-diacetates from aldehydes catalyzed by triethylamine-bonded sulfonic acid [Et3N–SO3H]Cl



Bronsted acidic ionic liquid, [Et3N–SO3H]Cl, catalyzed the reaction of acetic anhydride with aryl aldehydes under solvent-free condition. Various 1,1-diacetates are obtained using 15 mol% of  triethylamine-bonded sulfonic acid in satisfactory to excellent yields in very short reaction times at ambient temperature. Different groups including electron donating or electron withdrawing groups linked to benzene ring such as methyl, chloro, nitro and methoxy were tolerated under the optimized reaction conditions. This ionic liquid was air stable and easily prepared from accessible amine and chlorosulfonic acid. The present report is a green protocol as it eliminates the need of an organic solvent. Very short reaction times, high yields, simple operational procedure and green conditions are merits of this methodology.