Improved method for the synthesis of o-glycosylated fmoc amino acids to be used in solid-phase glycopeptide synthesis (Fmoc = fluoren-9-ylmethoxycarbonyl)

Abstract

The building blocks O¹-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-N^α-(fluoren-9-ylmethoxycarbonyl)serine (5) and O¹-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-N^α-(fluoren-9-ylmethoxycarbonyl)threonine (6) for use in solid-phase glycopeptide synthesis can be obtained via their ally esters by mild treatment with tetrakis(triphenylphosphine)palladium(0) and tributyltin hydride with no Fmoc elimination or sugar cleavage or anomerization.