Solid-Phase Synthesis of A-Linked Glycopeptides

The anthracenesulfonamide linkage was cleaved under mild, solid support compatible conditions such as thiophenol or 1,3-propanedithiol and Hiinig s base. 

Treatment of 70 with 1,3-propanedithiol and -Pr2NEt effected both the cleavage of the sulfonamide and the reduction of the azide to afford 71. 

Glycal assembly on a solid support eliminates the repetitive purifications usually associated with oligosaccharide synthesis. As a method, it has a certain generality as it does not require any specific enzymes or complex starting materials. Both natural and nonnatural sugars may be used in the constructions. 

A number of challenges still remain before a flexible, high-yielding, and absolutely selective strategy for the synthesis of oligosaccharides on the solid support becomes available. Once these problems are solved, the construction of an automated oligosaccharide synthesizer will become feasible. 

The rapid access to complex glycoconjugates will open the door to detailed studies concerning the structure and function of this class of biooligomers. 

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M Meldal, B Klaus. Pentafluorophenyl esters for temporary carboxyl group protection in solid phase synthesis of A-linked glycopeptides. Tetrahedron Lett 48, 6987, 1990. 

Vetter, D, Tumelty, D, Singh, S K, Gallop, M A, A versatile solid-phase synthesis of A-linked glycopeptides, Angew. Chem. Int. Ed., 34, 60-62, 1995. 

Meinjohanns, E, Meldal, M, Paulsen, H, Dwek, R A, Bock, K, Novel sequential solid-phase synthesis of A-linked glycopeptides from natural sources, J. Chem. Soc. Perkin Trans. 1, 549-560, 1998. 

Nakahara, Y, Nakahara, Y, Ogawa, T, Solid-phase synthesis of an O-linked glycopeptide based on a benzyl-protected glycan approach, Carbohydr. Res., 292, 71-81, 1996. 

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