Synthesis and Properties of Partially Saturated Fluorenyl‐Derived [
<i>n</i>
]Helicenes Featuring an Overcrowded Alkene
作者:Lenka Pallova、Etienne S. Gauthier、Laura Abella、Marion Jean、Nicolas Vanthuyne、Vincent Dorcet、Laure Vendier、Jochen Autschbach、Jeanne Crassous、Stéphanie Bastin、Vincent César
DOI:10.1002/chem.202100150
日期:2021.5.17
H6‐fluoreno[n]helicenes (n=5 or 7) featuring a central, overcrowded alkene is described. The key cyclization step was based on an intramolecular McMurry reaction from the corresponding 1,5‐diketones. Chiral stationary phase HPLC analysis and isomer separation indicate that each helicenic compound is constituted of three diastereoisomers at room temperature, i. e. the configurationally stable (R,R,P)/(S,S,M)
描述了部分饱和的 H 6 -氟代[ n ] helicenes ( n = 5 或 7)的直接、多克级合成,其特征是中心、过度拥挤的烯烃。关键的环化步骤基于相应 1,5-二酮的分子内 McMurry 反应。手性固定相 HPLC 分析和异构体分离表明,每种螺旋化合物在室温下均由三种非对映异构体组成,即。e. 构型稳定的 ( R,R,P )/( S,S,M ) 对映异构体和明显的非手性化合物,由 ( R,S,P ) 和 ( S,R,M ) 对映异构体之间的快速相互转化产生。部分饱和的H 6‐fluoroen[ n ] helicenes 被氧化芳构化,可以有效地获得相应的 fluoroen [ n ] helicenes。已经通过量子化学计算测量和分析了手性对映纯化合物的手性光学性质(振动和电子圆二色性),证实了它们的螺旋性质。