A Highly Regioselective and Solvent-Free Sn(II)-Catalyzed Glycerol Ketals Synthesis at Room Temperature

Herein, an efficient and environmentally benign tin-based process who is a simple and available commercially catalyst, was used in the glycerol ketalization with different ketones at room temperature and solvent-free reactions. Although being a molecule highly functionalized, glycerol was selectively converted to ketal in all the SnCl2-catalyzed reactions. A high regioselectivity (ca. 78-99 % for 1,3-dioxolane derivatives) was achieved for ketones with straight or cyclic chain having up to six carbon atoms. Conversely, glycerol ketalization with branched carbon chain ketones containing six carbon atoms (i.e. 4-methyl-2-pentanone) resulted in the equimolar formation of two isomers products (i.e. cis and trans-1,3-dioxolane isomers glycerol derivatives). The main reaction parameters such as the ketone nature, reactants stoichiometry and catalyst concentration were assessed. The SnCl2 catalyst operate at mild and solvent-free reaction conditions and was successively recovered and reused without activity loss.