Synthesis of 3-formyl-eudistomin U. (a) Ac2O, Et3N, DMAP, DCM, 0 oC ~ rt; (b) i, Trp-COOMe, methylbenzene, reflux; ii, DCM, TFA, 0 oC ~ rt; (c) Pd/C, xylene, 150 oC; (d) NaBH4, CaCl2, anhydrous EtOH, rt; (e) Dess-Martin periodinane, anhydrous DCM, 0 oC ~ rt