STUDIES ON CARBOHYDRATES XII.AN IMPROVED KOENIGS KNORR METHOD FOR HIGHLY STEREOSELECTIVE SYNTHESIS OF 1-O-ACYL-β-D-GALACTOPYRANOSE TETRAACETATES

摘要

2,3,4,6-Tetra-O-acetyl-α-D-galactopyranosyl bromide reacted with carboxylic acids in thepresence of CaH₂ and Ag₂CO₃ and small amount of I₂ to give good yields of l-O-acyl-β-D-galactopyranose tetraaeetates.β-Anomers of glycosyl esters were obtained by this improvedKoenigs-Knorr method.