Development of the synthetic study of polyene macrolides by the strategy based on completely controlled 1,3-diol synthesis

点击翻译按钮获取中文摘要

For the problem to achieve the total synthesis of polyene macrolide filipin 111 by the strategy based on chiral oxazaborolidinone-promoted asymmetric aldol reactions, the research was developed with some useful results. The synthesis of the starting aldehyde available for the 8 iterative 1.3-polyol (polyacetate systems) by using the aldol reactions was completed and was reported (Tetrahedron: Asymmetry 1999). It agreed with the result of synthesizing the product on the basis of the asymmetric Sharpless oxidation by Rychnovsky et al . And thus the effectiveness of our technique was shown. In addition, the following introduction reaction of 1,3-polyol was examined by the very simple technique with repetitive use of the asymmetric aldol reaction. The asymmetric synthesis of 7 iterative 1,3-syn-polyol was performed by the same technique. It was confirmed that the methodology which enables that new asymmetric center is introduced regardless of existing asymmetric centers is effective in not … More only filipin III of the purpose but also chain skeleton including various 1,3-syn and anti systems. However, though the rectilinear synthetic method is able to be trusted in the selectivity and the experimental procedure is convenient, in the case of the too long straight chain it was judged not to be efficient on the overall yield of the synthesis. Then a convergent approach was tried Two 1.3-polyol units were prepared by using our asymmetric aldol reaction, and the condensation between the units was tried. The total yield of the synthesis was remarkably improved by the parallel method. The condensation was carried out by using the asymmetric aldol reaction with silyl enol ether previously developed by us. The highly controlled asymmetric aldol reaction, accompanied with an asymmetric reduction can give a 1,3-syn-diol. By applying this reaction in the last stage, the asymmetric synthesis of a segment including all polyol parts of filipin III was achieved (Tetrahedron Lett. 2000). At present, the total synthesis is being completed. Less