A comparative study of different glycosylation methods for the synthesis of d-mannopyranosides of Nα-fluorenylmethoxycarbonyl-trans-4-hydroxy-l-proline allyl ester

The synthesis of Nα-fluorenylmethoxycarbonyl-trans-4-hydroxy-4-O-[(2,3,4,6-tetra-O-acetyl)-α-d-mannopyranosyl]-l-proline allyl ester and Nα-fluorenylmethoxycarbonyl-trans-4-hydroxy-4-O-[(2,3,4,6-tetra-O-benzoyl)-α-d-mannopyranosyl]-l-proline allyl ester is described. Glycosylation using Königs–Knorr conditions with a benzoyl protected glycosyl donor provided the optimum method. Removal of the allyl ester gave two mannosylated building blocks suitable for solid phase glycopeptide synthesis.