Total synthesis of cyclo-l-rhamnohexaose by a stereoselective thermal glycosylation
摘要:
The first cyclooligosaccharide of L series, cyclo-L-rhamnohexaose, have been synthesized from L-rhamnose by alpha-selective thermal glycosylation and PhSeOTf promoted cycloglycosylation.
Total synthesis of cyclo-l-rhamnohexaose by a stereoselective thermal glycosylation
摘要:
The first cyclooligosaccharide of L series, cyclo-L-rhamnohexaose, have been synthesized from L-rhamnose by alpha-selective thermal glycosylation and PhSeOTf promoted cycloglycosylation.
New Synthetic Methods and Reagents for Complex Carbohydrates. VIII. Stereoselective<i>α</i>- and<i>β</i>-Mannopyranoside Formation from Glycosyl Dimethylphosphinothioates with the C-2 Axial Benzyloxyl Group
The reactions of mannopyranosyl dimethylphosphinothioates and alcohols using silverperchlorate as an activator in the presence of molecular sieves 4A in benzene at room temperature gave the 1,2-trans-α-mannopyranosides in good yields. On the other hand, 1,2-cis-β-mannopyranosides could be obtained from the dimethylphosphinothioates by the combined use of iodine and 5 mol% triphenylmethyl perchlorate
1,2-cis-β-Mannopyranosides were obtained predominantly by reactions of mannopyranosyl dimethylphosphinothioate derivatives with several alcohols in the presence of iodine and a catalytic amount of triphenylmethyl perchlorate as the activator in benzene.