77 立体選択的1,3-ジオール類の合成法と糖誘導体の合成

概要

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New method for the stereoselective preparation of 1,3-diols from β-hydroxyketones are developed, and is successfully applied to the synthesis of 3-deoxy-hexoses. β-Hydroxyketones(1) are converted to their boron chelates by the treatment with tributylborane and cat. amount of air, and are successively reduced with sodium borohydride at low temperature to give meso-1,3-diol(2) stereoselectively. This method is applied successfully to the stereoselective and simple preparation of syn-7-octene-2,4-diol(5), the synthetic intermediate of nonactic acid. The present method for 1,3-asymmetric induction is also utilized for the synthesis of 3-deoxy-hexoses in stereoselective manner. The aldol reaction of methylglyoxal dimethylacetal and O,O'-isopropylidene-D-glyceraldehyde affords 4,5-anti-adduct(14) predominantly. The treatment of the adduct(14) with triisobutyl-borane and then with sodium borohydride gives 2,4-syn-diol(16) in high selectivity, which is readily converted to 3-deoxy-D-ribohexose(18). The alternative method to obtain anti-1,3-diol from β-hydroxy-ketone is established by the use of aluminium triisopropoxide. Namely, when 4,5-anti-adduct(14) is treated with aluminium triisopropoxide, 2,4-anti-diol(17) is yielded predominantly. 3-Deoxy-D-arabino-hexose(19) is synthesized by the deprotection of 17.
天然有機化合物討論会の論文
1981-09-10