2-Deoxy-β-d-erythro-pentofuranose: Hydroxymethyl Group Conformation and Substituent Effects on Molecular Structure, Ring Geometry, and NMR Spin−Spin Coupling Constants from Quantum Chemical Calculations

摘要: The effect of hydroxymethyl conformation (gg, gt, and tg rotamers about the C4−C5 bond) on conformational energies structural parameters (bond lengths, bond angles, torsions) 10 envelope forms biologically relevant aldopentofuranose, 2-deoxy-β-d-erythro-pentofuranose (2-deoxy-d-ribofuranose) 2, has been investigated by ab initio molecular orbital calculations at HF/6-31G* level theory. rotation induces significant changes in energy profile 2 (2gt 2tg exhibit one global minimum, whereas 2gg exhibits two nearly equivalent minima), changes, especially those are consistent with predictions based previously reported vicinal, 1,3- 1,4-oxygen lone pair effects. HF/6-31G*-optimized geometries were re-optimized using density functional theory (DFT, B3LYP/6-31G*), resulting structures used DFT NMR spin−spin coupling constants involving 13C (i.e.,...