Identification of the furanose ring conformations and the factors driving their adoption.

Three groups of furanoses with restricted freedom of rotation on the C3-C4, C2-C3, and C1-C2 bonds, respectively, are presented. Conformational analysis of these furanoses is conducted based on the proton nuclear magnetic resonance (H NMR) spectroscopy, density functional theory (DFT) calculations, and X-ray analysis. It is shown that the particular group of the presented furanoses is locked in the specific conformation. These are the T-like, the E-like, and the T-like conformation, respectively. Characteristic H NMR spectra of these three conformations are presented and the factors influencing the conformational preferences of the analyzed furanoses are discussed.