In previous studies of our research group, we have selectively generated a pool of new 4-thiazolidinones by three-component reaction, solvent-free and microwave-assisted, between an aldehyde derived from a carbohydrate, a heteroaromatic amine and thioglycolic acid.[i] More recently, we have studied the effect of the addition of a boron organocatalyst on the selective synthesis of a novel under the same reaction conditions.[ii] With the aim of exploring the best reaction conditions for the diastereoselective synthesis of the 1,4-thiazepan-3-ones and 4-thiazolidinones , we have studied not only the effect on solvent variation but also the aggregation of AlCl₃ or different zeolites as Lewis acid catalysts (mordenita, zeolite 13x and ZSM-5). The generation of the corresponding intermediates and reaction products were monitored by CG-MS, taking reaction aliquots every five minutes of reaction. The characterization of the intermediates and corresponding reaction products were performed by NMR spectroscopy. [i] Ocampo, R. A.; Quiroga, A. A.; Koll, L. C; Fascio, M.; D´accorso, N. B. Síntesis y caracterización de 4-tiazolidinonas unidas a heterociclos nitrogenados y sustituidas por un carbohidrato adecuadamente funcionalizado. XX Simposio Nacional de Química Orgánica. Argentina. Buenos Aires. 2015. [ii] Ocampo, R. A.; Quiroga, A. A.; D´accorso, N. B. Estudio de la síntesis estereo y diasteroselectiva de una nueva 1,4-tiazepan-3-ona sustituida por un hidrato de carbono utilizando irradiacion de microondas. XX Simposio Nacional de Química Orgánica. Argentina. Buenos Aires. 2017.