Direct Experimental Characterization of a Bridged Bicyclic Glycosyl Dioxacarbenium Ion by 1H and 13C NMR Spectroscopy: Importance of Conformation on Participation by Distal Esters was written by Upadhyaya, Kapil;Subedi, Yagya P.;Crich, David. And the article was included in Angewandte Chemie, International Edition in 2021.HPLC of Formula: 582-52-5 This article mentions the following:
Low-temperature NMR studies with a 4-C-methyl-4-O-benzoyl galactopyranosyl donor enable the observation and characterization of a bridged bicyclic dioxacarbenium ion arising from participation by a distal ester. Variable-temperature NMR studies reveal this bridged ion to decompose at temperatures above ≈ -30°C. In the absence of the Me group, the formation of a bicyclic ion is not observed It is concluded that participation by typical secondary distal esters in glycosylation reactions is disfavored in the ground state conformation of the ester from which it is stereo-electronically impossible. Methylation converts the secondary ester to a conformationally more labile tertiary ester, removes this barrier, and renders participation more favorable. Nevertheless, the minor changes in selectivity in model glycosylation reactions on going from the secondary to the tertiary esters at both low and room temperature argue against distal group participation being a major stereo-directing factor even for the tertiary system. In the experiment, the researchers used many compounds, for example, (3aR,5S,6S,6aR)-5-((R)-2,2-Dimethyl-1,3-dioxolan-4-yl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol (cas: 582-52-5HPLC of Formula: 582-52-5).
(3aR,5S,6S,6aR)-5-((R)-2,2-Dimethyl-1,3-dioxolan-4-yl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol (cas: 582-52-5) belongs to tetrahydrofuran derivatives. Tetrahydrofuran (THF), or oxolane, is mainly used as a precursor to polymers. Being polar and having a wide liquid range, THF is a versatile solvent. Tetrahydrofuran reaction with hydrogen sulfide: In the presence of a solid acid catalyst, tetrahydrofuran reacts with hydrogen sulfide to give tetrahydrothiophene.HPLC of Formula: 582-52-5
Referemce:
Tetrahydrofuran – Wikipedia,
Tetrahydrofuran | (CH2)3CH2O – PubChem