Laticyclic conjugated double bonds within the framework of oligocondensed bicyclo[2.2.2]octenes
作者:Wolfram Grimme、Jens Wortmann、Dirk Frowein、Johann Lex、Grace Chen、Rolf Gleiter
DOI:10.1039/a803481h
日期:——
The all-syn oligocondensed bicyclo[2.2.2]octenes 3, 5, 20 and 29 with two to five etheno bridges show interaction of their π-orbitals by σ-overlap. This laticyclic conjugation reveals itself in the PE and UV spectra of the series as well as in the site selectivity of the Diels–Alder reaction with inverse electron demand found for the dehydro derivatives 11 and 26. As shown in the crystal structures of 3, 5 and 20, the etheno bridges are positioned face to face at a distance which is smaller than the sum of their van der Waals radii.
所有顺式的低聚缩合双环[2.2.2]八烯3、5、20和29具有两个到五个乙烯桥,通过σ重叠展示了它们的π轨道之间的相互作用。这种环状共轭在该系列的光电子发射(PE)和紫外光(UV)光谱中显现出来,同时也体现在Diels–Alder反应的位点选择性中,后者在脱氢衍生物11和26中发现具有逆电子需求。正如3、5和20的晶体结构所示,乙烯桥之间是正面对面的,距离小于它们范德华半径的和。