Acid-catalysed formation of monoacetals from n-butyraldehyde and certain D-glucitol derivatives

Abstract

Acid-catalysed condensation of n-butyraldehyde with (a) 1-deoxy-D-glucitol yields a 2,3-acetal as a kinetically controlled product and the 2,4-acetal as the thermodynamically controlled product, (b) 2-deoxy-D-glucitol yields the 1,3-acetal as the kinetically controlled product and the 3,4-acetal(s) as the thermodynamically controlled product, and (c) 3-O-methyl-D-glucitol yields the 2,4-acetal as the predominant product throughout the reaction.In aqueous acid there is no evidence that 1,3-O-butylidene-2-deoxy-D-glucitol undergoes intramolecular conversion; instead substantial hydrolysis to the polyol and aldehyde occurs before the synthesis of the 3,4-acetal(s).