Synthesis of Non-Natural Branched Polysaccharides. Regioselective Introduction of α-Mannoside Branches into Chitin

Abstract
N-Phthaloyl-chitosan was converted into 3-O-acetyl-6-O-trimethylsilyl-N-phthaloyl-chitosan, which was then subjected to the glycosylation of a peracetylated mannose orthoester to form an α-(1→6) linkage. Subsequent deprotection followed by N-acetylation afforded chitins having mannose branches. The branched chitins were readily soluble in water and showed strong affinity for concanavalin A.