Steric control in the polymerization of 1,2-anhydro-3,4,6-tri-O-benzyl-beta-D-mannopyranose.
Polymerization of 1,2-anhydro-3,4,6-tri-O-benzyl-beta-D-mannopyranose under acid catalysis has led to a series of polymers varying in anomeric configuration from approximately 90% alpha to 70% beta. Optical rotations follow 13C-n.m.r. estimates of anomeric composition linearly over this range. Low-temperature polymerization with trifluoromethanesulfonic anhydride as initiator favors mainly cis-opening of the anhydro ring, presumably through the intermediary of a macroester. These results are compared with related glycosylation and polymerization reactions on 1,2-anhydro sugar derivatives, and some mechanistic conclusions are proposed.
D006027:Glycosides; D009682:Magnetic Resonance Spectroscopy; D008362:Mannosides; D011108:Polymers; D011134:Polysaccharides; D013237:Stereoisomerism
D006027:Glycosides; D008362:Mannosides; D011108:Polymers; D011134:Polysaccharides; C045126:1,2-anhydro-3,4,6-tri-O-benzyl-beta-mannopyranose