Macrotricyclic Steroid Receptors by Pd°-Catalyzed Cross-Coupling Reactions: Dissolution of cholesterol in aqueous solution and investigations of the principles governing selective molecular recognition of steroidal substrates
作者:Thomas Marti、Blake R. Peterson、Andreas Fürer、Tiziana Mordasini-Denti、Jürgen Zarske、Bernhard Jaun、François Diederich、Volker Gramlich
DOI:10.1002/hlca.19980810112
日期:1998.1.12
(Scheme 4). Solid cholesterol was efficiently dissolved in water through complexation by (±)-2 and (±)-3, and the association constants of the formed 1:1 inclusion complexes were determined by solid-liquid extraction as Ka = 1.1 × 106 and 1.5 × 105 l mol−1, respectively (295 K) (Table 1). The steroid-binding properties of the three receptors were analyzed in detail by 1H-NMR binding titrations in CD3OD.
制备了三个双层环烷受体,(±)-2,(±)-3和(±)-4,具有11–13-Å深的疏水腔,并研究了它们在水溶液和甲醇溶液中的类固醇结合特性。在这些新颖的大三环结构的构建中,钯催化的交叉偶联反应是关键步骤。在合成d 2 -symmetrical(±) - 2,双层前体(±) - 7在14%的收率由四倍得到的Stille与dibromocyclophane等摩尔量的二(三丁基锡烷基)乙炔的偶联5(方案1) 。用于制备大三环前体(±)-使用Sonogashira交叉偶联反应,用Me 3 SiCCH将二碘十二烷12中的15个D 2-对称(±)-3,二碘十二烷12进行二炔基化,得到13。随后的炔烃脱保护得到二乙炔基化的环烷14,其通过Glaser-Hay大环化反应以42%的产率转化为(±)-15(方案2)。经由大三环前体(±)-25实现了C 2对称圆锥形受体(±)-4的合成。,其通过二碘[6.1.6