P-53 チオマリノール類の合成研究(ポスター発表の部)

概要

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The polyketide derived marine natural product thiomarinols were isolated from the bacterium Alteromonas rava sp. nov. SANK 73390 and were found to exhibit potent antimicrobial activity. We report here our synthetic efforts directed toward the total synthesis of thiomarinols mainly focused on the diastereoselective construction of the tetrahydropyran core, which is a common structural unit for thiomarinols and contains four contiguous stereogenic centers. Treatment of the epoxy alcohols possessing Z-α,β-unsaturated ester or aldehyde moiety, derived from optically pure 20 or 23, with sodium hydride in CH_2Cl_2 provided the tetrahydropyrans 15, 22 and 26 with the desired stereochemistries diastereoselectively in excellent yields via the intramolecular oxy-Michael reaction. The aldehyde 26 thus obtained was converted to 30 which was then treated with trimethylsilylacetylene in the presence of "BuLi and BF_3・OEt_2 to give the acetylenic alcohol 31 possessing the requisite stereogenic centers for thiomarinols, in 89% yield as a single product. For the introduction of the C4-R hydroxyl group, the ester 28 was transformed to 33 with C3-4 olefin function.
天然有機化合物討論会の論文
2006-09-15