Hexabromotricyclobutabenzene and Hexabromohexaradialene: Their Nickel-Mediated One-Pot Syntheses and Crystal Structure
作者:Amnon Stanger、Nissan Ashkenazi、Roland Boese、Dieter Bläser、Peter Stellberg
DOI:10.1002/chem.19970030207
日期:1997.2
spectroscopy suggest that 3 is obtained as the syn-all-trans isomer 3 a, and the symmetric anti-all-trans isomer 3 b is not obtained at all. The X-ray structures of 3 a and 4 are reported. The hexaradialene 4 has a chair conformation, and deviates from planarity by 43.6 degrees . Heat or radical impurities cause the clean transformation of 3 a to 4.
六(二溴甲基)苯与[(Bu3 P)2-Ni(COD)](COD = 1,5-环辛二烯)在DMF中于65-70℃反应,得到标题化合物的混合物。通过柱色谱法分离混合物,分别以24%和16%的产率产生六溴代三环丁苯(3a)和六溴代六芳烃(4)。(1)H和(13)C NMR光谱表明,获得了3作为顺式全反式异构体3a,而完全没有获得对称的反式全反式异构体3b。报道了3a和4的X射线结构。六芳烃4具有椅子构型,并且与平面度偏离43.6度。热量或自由基杂质会导致3 a到4的干净转变。