Synthesis monosaccharides

T. Hudlicky, D. A. Entwistle, K. K. Pitzer, A. J. Thorpe, Modem methods of monosaccharides synthesis from non-carbohydrate sources, Chem. Rev. 96 1195 (1996). 

Hudlicky, T. et al. Modem Methods of Monosaccharide Synthesis from Non-Carbohydrate Sources. 1996 [25c]... 

C. Hager, R. Miethchen, and H. Reinke, Epimerisation of carbohydrates and cyclitols, 17. Syntheses of glycosyl azides and JV-acetyl glycosyl amines of rare monosaccharides. Synthesis... 

The potency of derivatives of 5,6-dihydro-2H-pyran (267) as convenient substrates for the synthesis of a variety of racemic sugars was demonstrated in the first volume " of this series. During the past decade these compounds continued to be used for many sugar syntheses, including syntheses of di- and trisaccharides. In fact, a general scheme of monosaccharide synthesis based on derivatives of... 

The basic mechanism is a disproportionation. Thus a disaccharide, such as sucrose, could give a triose and a free monosaccharide. Synthesis of a levan (i.e. a fructan) would be accompanied by the release of glucose, while the production of a dextran (i.e. a glucan) would liberate free fructose. By repeated transglycosylations of this type polymers arise. A similar mechanism occurs in the production of some plant fructans, but it is otherwise very rare in eukaryotes. Bacterial levans are usually much larger than their eukaryotic counterparts and other polymers produced in the same way include bacterial arabinans, xylans, galactans and glucans. 

It is clear, then, that perhaps no other group of compounds is as well suited to enzyme-based synthesis as is the carbohydrates. During the past several years, we have developed a range of enzyme-based syntheses for mono-, oligo-, and polysaccharides. This paper reviews some of our efforts on the use of aldolases and transketolase for monosaccharide synthesis, as well as the use of Leloir and non-Leloir pathway enzymes for glycosidic bond formation. 

FDP Aldolase. The most extensively utilized class of enzymes for monosaccharide synthesis are the aldolases (E.C. sub-class 4.1.2.). This ubiquitous group of enzymes catalyzes reversible aldol reactions in vivo. Two major groups of aldolases exist type I aldolases, found primarily in higher plants and animals, catalyze aldol condensations by means of a Schiff base formed between an enzyme lysine e-amino group and the nucleophilic carbonyl group type II aldolases, found primarily in microorganisms, utilize a divalent zinc to activate the nucleophilic component (79). Approximately 25 aldolases have been identified to date (18),... 

Aldolases have been studied as catalysts for monosaccharide synthesis for nearly 40 years. The best studied member of the group is a fructose-1,6-diphosphate (FDP) aldolase from rabbit muscle (RAMA, E.C. 4.1.2.13) (20), In vivo, this enzyme catalyzes the reversible condensation of D-glyceraldehyde-3-phosphate and dihydroxy acetone phosphate (DHAP) to generate FDP (Scheme 1). In the synthetic direction, the enzyme catalyzes the formation of two new stereogenic centers with absolute stereospecificity the stereochemistry of the new vicinal diol is always D-... 

Activated monosaccharides, synthesis using Leloir-pathway glycosyltransfeiases,... 

Watanabe, S., Sueyoshi, T, Ichihara, M., Uehara, C., and Iwamura, M., Reductive ring opening of o-nitrobenzyhdene acetals of monosaccharides synthesis and photolysis of some photolabile sugars, Org. Lett., 3, 255-257, 2001. 

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