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

We herein reveal the possibility of the C-4 neighboring\ngroup/remote\ngroup participation (NGP/RGP) facilitating the stabilization of the\nanomeric center via dioxolenium intermediates in the chemoselective\nactivation of glycal donors. We further realized that the <i>axial/equatorial</i> configuration of the C-4 group in the galacto-\nand gluco-glycal series enables diverse pathways to give direct 1,2-addition\nor Ferrier rearrangement, respectively. A proof-of-principle for stereoselective\nglycosylation was amply illustrated by employing carbohydrates, amino\nacids, natural products, and bioactive molecules to develop 2-deoxy-glycan\nanalogs.