Synthesis of mannose 6-phosphate-containing disaccharide threonine building blocks and their use in solid-phase glycopeptide synthesis

The preparation of 6′-O-phosphorylated α(1,2)- and α(1,6)-linked mannose disaccharides is described, starting from phenyl 2,3,4-tri-O-benzoyl-1-thio-α-D-mannopyranoside and using bis-(2,2,2-trichloroethyl)phosphorochloridate as phosphorylating reagent. The mannobiosides were converted into glycosyl donors and used in glycosylations of Nα-Fmoc-Thr-OPfp. The resulting glycosylated building blocks, 11 and 12, were used in solid-phase glycopeptide synthesis of O-mannosylated tripeptides.