Synthesis of Oligosaccharide Libraries

There are a few examples where mixtures of complex oligosaccharide have been isolated from natural sources such as bovine fetuin, porcine fibrinogen or conalbumin, and the mixture converted to the glycosyl amine and then coupled to an amino acid before separation of the individual components by HPLC. In one example described, 15 N-linked 

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While these advances make the synthesis of di-and trisaccharide combinatorial libraries a relatively facile process, the synthesis of oligosaccharide libraries (such as tetrasaccharides and higher derivatives) is still quite challenging. This is largely due to the fact that the present glycosylation methods are not quantitative. 

Izumi, M, and Ichikawa, Y, Combinatorial synthesis of oligosaccharide library of 2,6-dideoxysugars, Tetrahedron Lett., 39, 2079-2082, 1998. 

Scheme 15 Bidirectional strategy for the synthesis of oligosaccharide libraries.

Scheme 6.192 shows the o-nitrobenzyl moiety used as a photolabile linker in the solid-phase oligosaccharide synthesis on a polystyrene (PS) support.1208 After the synthesis of the protected oligosaccharide 404, PS attached to the photoremovable group is removed by photolysis and the final product is obtained by hydrogenolysis. Such a strategy could be promising for combinatorial synthesis of oligosaccharide libraries. 

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