Oligosaccharide stereoselective synthesis

Scheme 4.73 Glycosyl xanthates in stereoselective synthesis of galactosamine-containing oligosaccharides [399],...

Scheme 4.95 Stereoselective synthesis of oligosaccharides via glycosyl xanthate [399].

Through the development of effective methods for the stereoselective synthesis of L-glycero-D-manno-heptopyxanose, the synthesis of oligosaccharide structures, including this residue, became possible. Several good methods appeared at about the same time. 

Mereyala, H B, Reddy, G V, Directed, iterative, stereoselective synthesis of oligosaccharides by use of suitably 2-0-substituted 2-pyridyl 1-thioglycopyranosides on activation by methyl iodide. 

A. Schroven, S. Meinke, P. Ziegelmuller, and J. Thiem, Transsialidase from Trypanosoma cruzi for regio- and stereoselective synthesis of N-acyl-modified sialy lated oligosaccharides and measurement of transfer rates, Chem. Eur. J., 13 (2007) 9012-9021. 

H. Paulsen and W. Stenzel, Building units for oligosaccharides, IX. Stereoselective synthesis of a-glycosidically linked di- and oligosaccharides of 2-amino-2-deoxy-D-glucopyranose, Chem. Ber., 111 (1978) 2234-2347. 

Chemoenzymatic carbohydrate synthesis has been emerging as an extremely powerful tool to obtain complex oligosaccharides. Chemoenzymatic synthesis has many potential advantages, of which the most significant ones are probably that it offers perfect stereoselectivity and renders the tedious work of synthesizing various selectively protected monosaccharide units unnecessary. It also makes the most difficult glycosylation reactions seem easy (86). Chemoenzymatic synthesis of oligosaccharides is out of the scope of this chapter, but it was the topic of many excellent reviews (73,87-89). 

Ames X, Diaz Y, Castiiion S (2003) Phenyl-2-deoxy-2-iodo-l-thio-glycosides new glycosyl donors for the stereoselective synthesis of 2-deoxy-oligosaccharides. Synlett 14 2143-2146... 

Scheme 7.20. Solid-phase stereoselective synthesis of oligosaccharides using chiral auxiliary.

Rodriguez MA, Boutureira O, Ames X, Matheu MI, Diaz Y, Castillon S. Stereoselective synthesis of 2-deoxy-2-iodo-gly-cosides from furanoses. A new route to 2-deoxy-glycosides and 2-deoxy-oligosaccharides of ribo and xylo configuration. J. Org. Chem. 2005 70 10297-10310. 

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