Ethynyl[2.2]paracyclophanes are shown to be useful substrates for the preparation of complex, highly unsaturated carbon frameworks. Thus both the pseudo-geminal- 2 and the pseudo-ortho-diethynylcyclophane 4 can be dimerized by Glaser coupling to the respective dimers 9/10 and 11/12. Whereas the former isomer pair could not be separated so far, the latter provided the pure diastereomers after extensive column chromatography/recrystallization. Isomer 11 is chiral and could be separated on a column impregnated with cellulose tris(3,5-dimethylphenyl)carbamate. The bridge-extended cyclophane precursor 18 furnished the ring-enlarged cyclophanes 19 and 20 on Glaser–Hay coupling. Cross-coupling of 4 and the planar building block 1,2-diethynylbenzene (1) yielded the chiral hetero dimer 22 as the main product. An attempt to prepare the biphenylenophane 27 from the triacetylene 24 by CpCo(CO)2-catalyzed cycloisomerization resulted in the formation of the cyclobutadiene Co-complex 26. Besides by their usual spectroscopic and analytical data, the new cyclophanes 11, 12, 19, 20, 22, and 26 were characterized by X-ray structural analysis.
乙炔[2.2]对
联苯被证明是制备复杂、高度不饱和碳骨架的有用底物。因此,伪-
伪-
2 和伪-
邻-二
乙炔对
联苯 4 可以通过格拉瑟偶联反应二聚化成相应的二聚体
9/
10 和
11/
12。前者的异构体对目前尚无法分离,而后者在经过大量柱层析/结晶后提供了纯的对映异构体。异构体
11 是手性的,可以在浸渍有
纤维素三(3,5-二甲基苯基)
氨基甲酸酯的柱上分离。桥延伸的环对
联苯前体
18 在格拉瑟-海耦合反应中提供了环扩大的环对
联苯 19 和
20。
4 和平面构建块1,2-二
乙炔基苯(
1)的交叉偶联产生了手性杂二聚体
22 作为主要产物。尝试从三
乙炔 24 利用CpCo(CO)
2催化的环异构化反应制备
联苯对
联苯 27 导致
环丁二烯钴配合物
26 的形成。除了通常的光谱和分析数据外,新的环对
联苯 11、
12、
19、
20、
22 和
26 还通过X射线结构分析进行了表征。