An Fmoc-protected L-serine building block carrying a β-L-rhamnose residue, designed for solid-phase peptide synthesis (SPPS) of glycopeptides. The Nα-Fmoc group is removed under standard base conditions (piperidine) during chain elongation, while the free α-carboxylic acid is available for coupling to the growing resin-bound peptide. The sugar hydroxyl groups are protected as three acetate esters (Ac3), which keep the glycan inert during synthesis and are removed under mild base (e.g., sodium methoxide / hydrazine) after assembly. The installed glycan is an L-rhamnose residue, a non-mammalian sugar useful as a model building block and for anti-rhamnose antibody-recruitment research.