60 (+)-アブシジン酸および(-)-キサントキシンの簡便合成(ポスター発表の部)

概要

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Asymmetric syntheses of optically active abscisic acid and xanthoxin have been performed conveniently by an asymmetric induction method. Sharpless oxidation of cyclohexene methanol derivative(3), which was easily available by known method, and following Swern oxidation gave an asymmetric epoxy-aldehyde intermediate(6). Propagation of a side chain by Reformatsky reaction at the aldehyde group, followed by dehydration of the adduct with alkoxide, resulted in a stereospecific introduction of the side chain to obtain a key diene-intermediate(10). Transformation into optically active abscisic acid was performed simply in one step by treatment of 10 with hydrochloric acid. Acid treatment of the intermediate(10) under more mild condition resulted in selective removal of cyclic acetal to form keto-epoxide(12). Stereospecific reduction of the ring-calbonyl group with K-Selectride gave a β-hydroxy derivative(14β) preferentially. Conversion of the terminal ester group in 14β to aldehyde via LAH reduction followed by MnO_2 oxidation gave optically active xanthoxin successfully.
天然有機化合物討論会の論文
1990-09-25