THIOGLYCOSIDES AS POTENTIAL GLYCOSYL DONORS IN ELECTROCHEMICAL GLYCOSYLATION REACTIONS .1. THEIR PREPARATION AND REACTIVITY TOWARD SIMPLE ALCOHOLS

Constant potential electrolysis of several glycosyl donors such as sub stituted phenyl 2,3,4,6-tetra-O-acetyl, benzoyl or benzyl-1-thio-beta- D-gluco or galactopyranosides in dry acetonitrile in the presence of v arious primary, secondary or tertiary alcohols performed in an undivid ed cell, gave preferentially beta-linked saccharides in moderate to go od yields according to the nature of the protective groups on the suga r moiety. 2-Deoxy-2-phthalimido-1-thio-beta-D-gluco derivatives gave t he beta-glucosides selectively in excellent yields. It was found, as e xpected, that substitution of the phenyl group with methoxy or methyl radicals facilitates the electrochemical glycosylation reaction by low ering the oxidation potentials of the corresponding thioglycosides.