Epoxidation of trans-cinnamyl alcohol (A) gives compound (I), which in turn is reacted with sodium 2-ethoxyphenate (B) to give the diol (II). The primary alcoholic group of (II) is reacted with p-nitrobenzoyl chloride to obtain (III), and (IV) is prepared by treatment of (III) with methanesulfonyl chloride. By treatment of (IV) with sodium hydroxide in an aqueous/dioxane solution the epoxide (V) is obtained in high yield, and this reaction causes inversion of configuration at C-2 carbon atom. Treatment of (V) with aqueous methanolic ammonia gives (VI), which in turn is acylated to (VII) with chloroacetyl chloride and cyclized to morpholone (VIII) with potassium tert-butoxide. The reduction to the final compound FCE-20124 is performed with [sodium bis(2-methoxyethoxy)aluminum hydride] (RED-AL) in toluene.