Influence of C‑4 <i>Axial/Equatorial</i> Configuration and Neighboring Group/Remote Group Participation (NGP/RGP) Driven Conformational Evidence in Chemoselective Activation of Glycals

We herein reveal the possibility of the C-4 neighboring group/remote group participation (NGP/RGP) facilitating the stabilization of the anomeric center via dioxolenium intermediates in the chemoselective activation of glycal donors. We further realized that the axial/equatorial configuration of the C-4 group in the galacto- and gluco-glycal series enables diverse pathways to give direct 1,2-addition or Ferrier rearrangement, respectively. A proof-of-principle for stereoselective glycosylation was amply illustrated by employing carbohydrates, amino acids, natural products, and bioactive molecules to develop 2-deoxy-glycan analogs.