macrocycles and monodisperse acyclic oligomers with conformationally less flexible backbones were synthesized in enantiomerically pure form by short, high‐yielding routes starting from optically active 1,3‐diethynylallenes. All seven stereoisomers—two pairs of enantiomers and three achiral stereoisomers—in the macrocyclic series were separated and configurationally assigned. The electronic circular dichroism
从光学活性的1,3-二
乙炔基
丙二烯开始,通过短而高产的路线,以对映体纯净的形式合成了第二组形状持久的异源-炔属大环化合物和构象较不灵活的主链的单分散无环低聚物。大环系列中的所有七个立体异构体(两对对映异构体和三个非手性立体异构体)均已分离并进行了构型分配。所述的电子圆二色性(
ECD)光谱d 2 -对称,(P,P,P,P和( - )中号,中号,中号,中号)配置的大周期显示出非常强烈的按摩反应。在无环寡聚系列中观察到手性的强烈扩增。X射线分析和计算研究证明了他们偏爱单手螺旋形二级结构。这组新的数据提供了证明,出色的
ECD响应是异位炔炔大环和无环寡聚发色团的标志。