Layered Compounds. V. Synthesis and Properties of [<i>m</i>.<i>n</i>]Paracyclophadiynes
作者:Takahiro Matsuoka、Taichi Negi、Tetsuo Otsubo、Yoshiteru Sakata、Soichi Misumi
DOI:10.1246/bcsj.45.1825
日期:1972.6
A series of bisethynyl compounds, IX and XII, were prepared by a modified ethynylation using N-methyl-2-pyrrolidone in good yields. Intramolecular oxidative coupling of the bisethynyl compounds has been achieved with high-dilution technique to give relatively good yields of highly strained or strainless [m.n]paracyclophadiynes I and cyclic diacetylenes XIII. From the comparison of the electronic spectra of these diacetylenic compounds, it is concluded that abnormal spectra of Ic and Id are attributed to the transannular π-electronic interaction between benzene nucleus and diacetylenic unit rather than the ring strain in the molecules. In addition, a marked down-field shift of aromatic protons in Ic compared with the other paracyclophadiynes is explained in terms of the transannular shielding effect of diacetylenic linkage.
一系列双乙炔基化合物IX和XII通过改良的乙炔化反应,使用N-甲基-2-吡咯烷酮,以良好的产率制备得到。采用高度稀释技术实现了双乙炔基化合物的分子内氧化偶联反应,得到了高张力或无张力的[m.n]型聚环对二炔I和环状二乙炔XIII,产率相对较好。通过比较这些二乙炔化合物的电子光谱,得出结论:Ic和Id的异常光谱归因于苯环核与二乙炔单元之间的跨环π电子相互作用,而不是分子内的环张力。此外,与其他聚环对二炔相比,Ic中芳香质子的明显低场位移,可以用二乙炔连接的跨环屏蔽效应来解释。