Total Synthesis and Bioactivity of an Unnatural Enantiomer of Merrilactone A: Development of an Enantioselective Desymmetrization Strategy
作者:Masayuki Inoue、Nayoung Lee、Satoshi Kasuya、Takaaki Sato、Masahiro Hirama、Miyako Moriyama、Yoshiyasu Fukuyama
DOI:10.1021/jo0700474
日期:2007.4.1
associated with Alzheimer's and Parkinson's diseases. Apart from its biological aspects, the caged pentacyclic skeleton of 1 poses interesting synthetic challenges. Here, we report the total synthesis of the unnatural enantiomer of merrilactone A [(+)-1], based on a novel desymmetrization strategy. The chiral lithium amide 16g promoted an enantioselective transannular aldol reaction of eight-membered meso-diketone
( - ) - Merrilactone A [( - ) - 1 ],从分离的八角merrillianum于2000年,具有神经突向外生长的活性在胎鼠皮质神经元的培养物,并且,因此,预计将显示治疗潜力为神经变性的与相关联的处理阿尔茨海默氏病和帕金森氏病。除了其生物学方面,笼状的五环骨架1提出了有趣的合成挑战。在这里,我们报告了基于一种新型的非对称化策略的merrilactone A [(+)- 1 ]非天然对映异构体的总合成。手性氨基锂16g促进了八元内消旋二酮的对映选择性环过醛羟醛反应如图3d所示,一步建立了1的顺式-双环[3.3.0]辛烷骨架的四个手性中心的绝对立体化学。所获得的化合物4d用作构建(+)- 1所需的后续官能团操作的平台。出人意料的是,合成的merrilactone A的天然和非天然对映异构体均在原代神经元培养物中同样促进神经突生长。