Dimerization of aldosuloses and aldonolactones into branched higher carbon sugars

Abstract

Homo-dimerizations of a variety of aldosulose and aldonolactone derivatives via aldol and Claisen reactions have been achieved, leading to novel branched higher carbon sugars in a highly stereoselective manner.

Solving the Structural Puzzles of Amipurimycin and Miharamycins Enabled by Stereodivergent Total Synthesis

“…3) The aldol condensation of furanose 3‐ketone 58 with methyl ketone 57 in the presence of NaHMDS led to adduct 59 in a highly stereoselective manner, in which the configuration of C‐3 (intended C‐3′) was controlled by furanose 58 owing to its substituents being all at the α face. Interestingly, self‐condensation of the furanose ketone could take place [25] . 4) The α‐amino carbons in ketones 59 and 60 were prone to epimerization under basic conditions, hence, lower temperature, shorter reaction time or acidic conditions were adopted.…”

“…Interestingly, self-condensation of the furanose ketone could take place. [25] 4) The α-amino carbons in ketones 59 and 60 were prone to epimerization under basic conditions, hence, lower temperature, shorter reaction time or acidic conditions were adopted. 5) The desired stereochemistry at C5' in 1 a was stereoselectively established through a chelation-controlled Luche reduction of ketone 60 with NaBH 4 /CeCl 3 (d.r.…”

Synthesis of C-Oligosaccharides via Ni-Catalyzed Reductive Hydroglycosylation

“…Glycans play crucial roles in a myriad of biological processes, such as cell adhesion, the immune response, inflammation, cancer metastasis, and viral and bacterial infections . Compared to the native glycans that are assembled mostly via O -glycosidic linkages, C -linked glycans ( C -oligosaccharides) could retain the biological and pharmacological properties while being metabolically stable, making them artificial surrogates and/or mimics of the native glycans with therapeutic potential. , For instance, the C -trisaccharide analogue of the H-type II blood group is metabolically stable while maintaining a binding affinity and biological activities identical to those of the native glycan (Figure a); tunicamycins, the natural nucleoside antibiotics possessing a tail-to-tail C–C linkage between the ribose and GalN units, can inhibit bacterial phosphor- N -acetylmuranyl-pentapeptide transferase (MraY) with an IC 50 value of 0.35 μM.…”