Coupling of decanoylchloride (I) with D-serine (II) under Schotten-Baumann conditions (with Na2CO3 in H2O/THF) provides N-decanoyl-D-serine (III). Separately, aldehyde (IV) is reduced by means of NaBH4 in EtOH to yield alcohol (V), whose nitro group is reduced by means of In and NH4Cl in EtOH to afford substituted aniline (VI). Coupling of 5-amino-2-hydroxybenzyl alcohol (VI) with serine (III) by means of dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole (HOBt) in DMF furnishes compound (VII), which is finally oxidized with NaIO4 in MeOH/H2O to yield the desired spiroepoxide.