Synthesis of β-1,4-Linked Galactan Side-Chains of Rhamnogalacturonan I

The synthesis of linear‐ and (1→6)‐branched β‐(1→4)‐d‐galactans, side‐chains of the pectic polysaccharide rhamnogalacturonan I is described. The strategy relies on iterative couplings of n‐pentenyl disaccharides followed by a late stage glycosylation of a common hexasaccharide core. Reaction with a covalent linker and immobilization on N‐hydroxysuccinimide (NHS)‐modified glass surfaces allows the generation of carbohydrate microarrays. The glycan arrays enable the study of protein–carbohydrate interactions in a high‐throughput fashion, demonstrated herein with binding studies of mAbs and a CBM. The chemical synthesis of nine linear and branched galactan oligosaccharides related to the plant cell‐wall polysaccharide pectin is reported. The target molecules allow the detailed study of carbohydrate–protein interactions, as exemplified for two mAbs and a CBM here (see scheme).