Layered Compounds. XVIII. Synthesis of a Paracyclophane Containing the 1,2,3,4,5-Hexapentaene Group and the Stereochemistry of Its Formation
作者:Taichi Negi、Takahiro Kaneda、Hiroshi Mizuno、Toshihiro Toyoda、Yoshiteru Sakata、Soichi Misumi
DOI:10.1246/bcsj.47.2398
日期:1974.10
Novel cyclic 1,2,3,4,5-hexapentaene compounds were synthesized from cyclic diyne-diol IX via diallene-dibromide X in order to study transannular electronic interaction. A diallene-dibromide Xc-I obtained from a diyne-diol isomer IXc-I was debrominated with active zinc to give cyclic hexapentaene IIc, whereas the other diallene-dibromide Xc-II derived from the second diyne-diol isomer IXc-II was not. The X-ray crystallographic analysis of the dibromide Xc-I was then carried out, and the s-trans structure was assigned to the dibromide. On the basis of this result, the stereochemistry of the transformation from diyne-diol to the hexapentaene group was discussed. The electronic spectrum of a cyclophane IIa containing the hexapentaene group showed a transannular π-electronic interaction between the benzene ring and the hexapentaene group, unlike those of the other hexapentaene derivatives, IIc and XV.
为了研究跨annular 电子相互作用,我们从环状二炔二醇 IX 通过二烯二溴化物 X 合成了新型环状 1,2,3,4,5-hexapentaene 化合物。从二炔二醇异构体 IXc-I 中得到的二炔二溴化物 Xc-I 与活性锌脱溴后得到环己五烯 IIc,而从第二个二炔二醇异构体 IXc-II 中得到的另一种二炔二溴化物 Xc-II 则没有脱溴。随后对二溴化物 Xc-I 进行了 X 射线晶体学分析,并确定了该二溴化物的 s-trans 结构。在这一结果的基础上,讨论了从二炔二醇转变到六方戊烯基团的立体化学过程。含有己五烯基团的环烷 IIa 的电子能谱显示,苯环与己五烯基团之间存在反π电子相互作用,这与其他己五烯衍生物 IIc 和 XV 不同。