Stereoselective Total Synthesis of Macrophage-Produced Prohealing 14,21-Dihydroxy Docosahexaenoic Acids
作者:Keita Nishimura、Tsuyoshi Sakaguchi、Yutaro Nanba、Yuta Suganuma、Masao Morita、Song Hong、Yan Lu、Bokkyoo Jun、Nicolas G. Bazan、Makoto Arita、Yuichi Kobayashi
DOI:10.1021/acs.joc.7b02510
日期:2018.1.5
Synthesis of 14S,21R- and 14S,21S-dihydroxy-DHA (diHDHA) among the four possible stereoisomers of 14,21-diHDHA was studied. Methyl (R)-lactate (>97% ee), selected as a C20–C22 fragment (DHA numbering), was converted to the C17–C22 phosphonium salt, which was subjected to a Wittig reaction with racemic C16-aldehyde of the C12–C16 part with the TMS and TBS-oxy groups at C12 and C14, yielding the C12–C22
研究了 14,21-diHDHA 的四种可能立体异构体中 14 S ,21 R - 和 14 S ,21 S-二羟基-DHA (diHDHA) 的合成。选择作为 C20-C22 片段(DHA 编号)的( R )-乳酸甲酯(>97% ee)转化为 C17-C22 鏻盐,然后与 C12 的外消旋 C16-醛进行 Wittig 反应-C16 在 C12 和 C14 处与 TMS 和 TBS-氧基部分结合,产生具有 14 R / S和 21 R手性的 C12-C22 衍生物。使用l -(+)-DIPT/Ti(O- i -Pr) 4对 TBS 脱保护的烯丙醇进行 Sharpless 不对称环氧化的动力学拆分得到 14 S-环氧醇和 14 R-烯丙醇,两者的非对映体过量 (de) 大于 99%。CN 基团通过与 Et 2 AlCN反应引入环氧醇。14 R-烯丙醇也通过光信转化转化为腈。用 DIBAL 还原腈得到对应于