A convergent approach to (R)-Tiagabine by a regio- and stereocontrolled hydroiodination of alkynes
作者:Giuseppe Bartoli、Roberto Cipolletti、Giustino Di Antonio、Riccardo Giovannini、Silvia Lanari、Mauro Marcolini、Enrico Marcantoni
DOI:10.1039/c005042c
日期:——
The occurrence of unsaturated systems in natural products combined with the mildness and the wide range of applicability of CeCl3 promoted methodologies suggest several potential future synthetic applications within the field of total synthesis of biologically active molecules. On this concept, the use of CeCl3·7H2O–NaI system as an efficient heterogeneous promoter has been highlighted in the iodofunctionalization of carbon–carbon triple bonds. The study has shown that this method would be particularly interesting for the stereoselective formation of trisubstituted (Z)- or (E)-iodoalkenes by simply changing the nature of the solvent. The methodology has been successfully applied to the synthesis of (R)-1-[4,4-bis-(3-methyl-2-thienyl)-3-butenyl]-3-piperidinecarboxylic acid 1, named (R)-Tiagabine, which is a potent and selective γ-aminobutyric acid (GABA) uptake inhibitor with proven anticonvulsant efficacy in humans.
不饱和体系在天然产物中的出现,以及CeCl3促进的方法所具有的温和性和广泛的适用性,提示在生物活性分子的全合成领域存在多个潜在的未来合成应用。在这个概念下,使用CeCl3·7H2O–NaI体系作为有效的异相促进剂,在碳-碳三重键的碘功能化中得到了强调。研究表明,这种方法对于立体选择性合成三取代的(Z)或(E)碘烯特别有趣,只需改变溶剂的性质。该方法已成功应用于合成(R)-1-[4,4-双-(3-甲基-2-噻吩基)-3-丁烯基]-3-哌啶甲酸1,即(R)-Tiagabine,这是一种有效且选择性的γ-氨基丁酸(GABA)摄取抑制剂,在人类中具有经过验证的抗癫痫疗效。