合成路线图解说明: 2-Naphtalenethiol (I) was treated with ethyl 4-bromobutyrate (II) and NaH to give thioether (III). Alkylation of (III) with isobutyl iodide (IV) in the presence of LDA afforded racemic (V), which was then hydrolyzed to the acid (VI) on treatment with litium hydroxide. Coupling of racemic acid (VI) with (S)-leucinol (VII) yielded a mixture of diastereomeric amides, which were separated by column chromatography. Diastereoisomer (VIII) was oxidized with m-chloroperbenzoic acid to give sulfone (IX), and was further oxidized with DMSO and sulfur trioxide-pyridine complex to produce the target aldehyde. |