The α-aminooxy derivative of the Thomsen-Friedenriech tumor associated carbohydrate antigen has been synthesized in 11 steps utilizing a D-GalN3 acceptor carrying a pre-installed α-N-hydroxysuccinimidyl moiety. The natural α linkage was prepared in high selectivity employing a suitably protected D-GalN3-thioglycoside donor with N-hydroxysuccinimide. With access to α-TF-ONH2, the preparation of the TF-PS A1 vaccine candidate ensued smoothly through oxime bond formation.