iii iv a Reagents and conditions: (i) SPPS by hand using HBTU/HOBt as coupling reagents, DIPEA, DMF, coupling was monitored by microcleavage of a small portion of the resin with 95% TFA, followed by HRMS analysis; (ii) peptide synthesis, acidic cleavage, and RP-HPLC purification; (iii) NaOMe, MeOH; (iv) 2 M NH4OAc. To conclude, we report the synthesis of the triple-modified plant peptide hormone PSY1, which is a glycopeptide that contains β-1,2-linked arabinose carbohydrates in combination with a hydroxyproline and sulfated tyrosine. Stereoselective glycosylation of hydroxyproline with L-arabinofuranoside was achieved by intramolecular aglycon delivery (IAD) using a PMB ether on the C2 hydroxyl group. This resulted in three Fmoc-protected building blocks that are compatible with Fmocbased solid-phase peptide synthesis (SPPS) using HBTU/HOBt as coupling reagents for the introduction of Fmoc-Hyp[(L-Ara)]1-3-OH 14-16 and Fmoc-Hyp(tBu)-OH 9. Elongation to the PSY1 (glyco)peptide to form derivatives 20-23 was done using an automated peptide synthesizer. Target peptides were obtained by initial removal of acetyl groups and subsequent Np removal. With this, we disclose a robust synthesis approach for the preparation of complex post-translationally modified peptides, especially those containing a sulfated tyrosine and arabinosylated hydroxyproline units, that will be useful for the preparation of peptides for phenotypical biological evaluation such as their role in intercellular signaling.