Upadhyaya, Kapil; Bagul, Rahul S.; Crich, David published the artcile< Influence of Configuration at the 4- and 6-Positions on the Conformation and Anomeric Reactivity and Selectivity of 7-Deoxyheptopyranosyl Donors: Discovery of a Highly Equatorially Selective L-glycero-D-gluco-Heptopyranosyl Donor>, Formula: C12H20O6, the main research area is structure property stereoselective glycosylation glycoside disaccharide preparation; nucleophilic substitution hydrogen bonding glycosyl triflate neuraminic ulosonic acid; stereoselective glycosylation glycoside preparation configuration conformation deoxyheptopyranosyl disaccharide NMR.
The preparation of four per-O-benzyl-D- or L-glycero-D-galacto and D- or L-glycero-D-gluco heptopyranosyl sulfoxides and the influence of their side-chain conformations on reactivity and stereoselectivity in glycosylation reactions are described. The side-chain conformation in these donors is determined by the relative configuration of its point of attachment to the pyranoside ring and the two flanking centers in agreement with a recent model. In the D- and L-glycero-D-galacto glycosyl donors, the D-glycero-D-galacto isomer with the more electron-withdrawing trans,gauche conformation of its side chain was the more equatorially selective isomer. In the D- and L-glycero-D-gluco glycosyl donors, the L-glycero-D-gluco isomer with the least disarming gauche-gauche side-chain conformation was the most equatorially selective donor. Variable temperature NMR studies, while supporting the formation of intermediate glycosyl triflates at -80°C in all cases, were inconclusive owing to a change in the decomposition mechanism with the change in configuration. It is suggested that the equatorial selectivity of the L-glycero-D-gluco isomer arises from H-bonding between the glycosyl acceptor and O6 of the donor, which is poised to deliver the acceptor anti-periplanar to the glycosyl triflate, resulting in a high degree of SN2 character in the displacement reaction.
Journal of Organic Chemistry published new progress about Conformation. 4064-06-6 belongs to class alcohols-buliding-blocks, and the molecular formula is C12H20O6, Formula: C12H20O6.
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