REGIOSELECTIVELY MODIFIED STEREOREGULAR POLYSACCHARIDE .1. POLYMERIZATION OF 1,6-ANHYDRO-3-O-ACETYL-2,4-DI-O-BENZYL-BETA-D-GLUCOPYRANOSE AND SYNTHESIS OF 2,4-DI-O-BENZYL-(1-]6)-ALPHA-D-GLUCOPYRANAN

An anhydro sugar having two different blocking groups, 1, 6-anhydro-3-0-acetyl-2, 4-di-O-benzyl-β-D-glucopyranose, was polymerized with PF5 as catalyst at temperatures ranging from 0 to -78 ΰC. Polymerization at -60 ΰC or below gave a highly stereoregular polymer. Subsequent deacetylation was successful with the use of DMF-methanol containing a small amount of sodium methoxide. Physical and spectral properties of these stereoregular, linear, polysaccharide derivatives were presented. A characteristic relationship was observed for the 13C NMR chemical shifts of 1, 6-anhydro-i3-D-glucopyranose and the corresponding (1→6)-α-D-glucopyranan derivatives. The 2, 4-di-O-benzyl-(l→6)-α-D-glucopyranan obtained will serve as a starting material for synthesis of new, useful polysaccharides. © 1979, American Chemical Society. All rights reserved.