An efficient synthesis of 2-[(1R)-(3-butoxycarbonylamino) -1-methylpropyl]-1,3-oxazole-4-methanol (2)corresponding to the antipode of the oxazole part. [N(3)-C(26) part) of calyculins A, B, E, and F (1), potent cytotoxic substances from a marine sponge, has been accomplished from methyl (S)-3-hydroxy-2-methylpropionate (3).The method involves oxazoline formation followed by oxidation to the oxazole.