Total Synthesis of the Neuronal Cell-Protecting Carbazole Alkaloids Carbazomadurin A and (<i>S</i>)-(+)-Carbazomadurin B
作者:Yuhzo Hieda、Tominari Choshi、Haruto Fujioka、Satoshi Hibino
DOI:10.1002/ejoc.201301059
日期:2013.11
The total syntheses of the neuronal cell-protecting carbazole alkaloids carbazomadurin A and (S)-(+)-carbazomadurin B were achieved. The key step of the synthesis of the polysubstituted carbazole rings included an allene-mediated electrocyclic reaction of the 6π-electron system that involved the indole 2,3-bond. The cleavage of the alkoxy groups of the resulting 3-ethoxy-8-isopropoxycarbazole successfully
实现了神经元细胞保护咔唑生物碱carbazomadurin A和(S)-(+)-carbazomadurin B的全合成。合成多取代咔唑环的关键步骤包括涉及吲哚 2,3-键的 6π 电子系统的丙二烯介导的电环反应。所得 3-乙氧基-8-异丙氧基咔唑的烷氧基裂解成功得到 3,8-二羟基咔唑,将其转化为 3,8-双(OSEM)-咔唑(SEM = 2-三甲基甲硅烷基乙氧基甲基)。3,8-双(OSEM)-咔唑与相应的烯基频哪醇硼酸盐的 Suzuki-Miyaura 交叉偶联反应得到 1-烯基咔唑,用四正丁基氟化铵 (TBAF) 处理,然后用 NaBH4 还原分别提供carbazomadurin A和(S)-(+)-carbazomadurin B。