Scheme 4. Synthesis of Globo H derivatives. Reagents and conditions: a) 1 M NaOH, THF, 50 °C, overnight; b) anhydride of corresponding carboxylic acid, pyridine, DMAP; for compound G1, CH2FCOCl, pyridine, DMAP; c) H2, Pd(OH)2/C, THF/HOAc/H2O, 64% for compound G0, 47% for compound G1, 61% for compound G2, 66% for compound G3, over three steps.
