Synthesis of α-d-Idoseptanosyl Glycosides Using an S-Phenyl Septanoside Donor

Abstract

[reaction: see text] An S-phenyl alpha-D-idoseptanoside donor was used in the selective preparation of a series of alpha-D-idoseptanosyl glycosides. Glycosylation of a methyl beta-D-glycero-D-guloseptanoside acceptor with the new donor constituted the first synthesis of a septanose disaccharide.

Total Synthesis and Biological Evaluation of (+)‐Gambieric Acid A and Its Analogues

“…The configuration of the newly formed C26 stereogenic center was determined by an NOE experiment, as shown in Figure 3, and the stereoselectivity of the allylation of 71 was in accordance with that observed for the O ‐glycosylation of septanosides 53. The stereochemical outcome can be explained by a stereoelectronic effect (Figure 4 A).…”

Conformational analysis of methyl 5-O-methyl septanosides: effect of glycosylation on conformer populations

“…We have also used 13 C chemical shifts as diagnostics for anomeric configuration of septanosides in previous systems. In the limited examples we have collected, 7,14,17,18 the trend is that d C1 of b-septanosides is slightly downfield relative to a-septanosides. The 13 C NMR measured values for d C1 of 3 is 106.1 ppm and that of 4 is 109.3 ppm.…”

“…While a methyl group is perhaps a small surrogate for an oligosaccharide linked via a glycosidic bond, some prior reports with furanosides suggest that this model can provide a great insight. 14 Indeed, we were interested in determining if glycosylation at C5 of septanoses 1 and 2 would change the distribution of their preferred conformers as has been observed in other carbohydrate systems. 12 Defining diseptanoside structures that contain either an a-(1!5)-linkage or a b-(1!5)-linkage are valuable to us because they approximate the natural disaccharides maltose and cellobiose.…”

Participation of Alkoxy Groups in Reactions of Acetals: Violation of the Reactivity/Selectivity Principle in a Curtin–Hammett Kinetic Scenario

“…This approach is used extensively in carbohydrate chemistry, where a substituent at the 2-position, usually an acyloxy group, controls the stereochemical configuration of substitution. [2-4] An acyloxy group can form a fused ring system resembling 1 (Figure 1), and opening of the five-membered ring by a nucleophile installs the nucleophile trans to the participating group. [2,5] Acyloxy groups at remote positions can also exert influences on stereoselectivity.…”