New design concepts for constraining glycosylated amino acids

In an effort to probe the mechanism by which glycosyltransferases recognize glycoproteins and assemble the core structures of O-linked oligosaccharides, two constrained glycopeptides based on the α-N-acetylgalactosaminyl serine substructure were chosen for synthesis. These compounds representing one of the two possible gauche conformations of the d-serine and l-serine configurations of the parent substructure were successfully prepared in reasonable overall yield through a convergent strategy.