Total Syntheses of β-Carboline Alkaloids, (<i>R</i>)-(−)-Pyridindolol K1, (<i>R</i>)-(−)-Pyridindolol K2, and (<i>R</i>)-(−)-Pyridindolol
作者:Naoko Kanekiyo、Takeshi Kuwada、Tominari Choshi、Junko Nobuhiro、Satoshi Hibino
DOI:10.1021/jo0105585
日期:2001.12.1
The total syntheses of beta-carboline alkaloids, (R)-(-)-pyridindolols (1, 5, and 6) are described. The two key steps involved are (1) a thermal electrocyclic reaction of the 3-alkenylindole-2-aldoxime 10 and (2) a thermal cyclization of 3-alkynylindole-2-aldoxime 11 to construct the beta-carboline N-oxides 8, which upon heating with acetic anhydride and sequential treatment with trifluoromethanesulfonic
描述了β-咔啉生物碱,(R)-(-)-吡啶并吲哚酚(1、5和6)的总合成。涉及的两个关键步骤是(1)3-烯基吲哚-2-醛肟10的热电环反应和(2)3-炔基吲哚-2-醛肟11的热环化以构建β-咔啉N-氧化物8将其用乙酸酐加热并依次用三氟甲磺酸酐处理得到三氟甲磺酸酯18。18与乙烯基锡烷的Stille偶联反应,然后裂解MOM醚,得到1-乙烯基-3-羟甲基-β-咔啉(7a)。随后的7a乙酰化,生成乙酸盐7b,将其通过AD-mix-beta进行Sharpless不对称1,2-二羟基化反应,生成(R)-(-)-吡啶醇K2(6)。通过Ac(2)O和可力丁实现6的选择性乙酰化,形成(R)-(-)-吡啶吲哚K1(5)。相反,6的水解提供了(R)-(-)-吡啶吲哚醇(1)。