Computational Assessment of the Electronic Structure of 1-Azacyclohexa-2,3,5-triene (3<i>δ</i><sup>2</sup>-1<i>H</i>-Pyridine) and Its Benzo Derivative (3<i>δ</i><sup>2</sup>-1<i>H</i>-Quinoline) as well as Generation and Interception of 1-Methyl-3<i>δ</i><sup>2</sup>-1<i>H</i>-quinoline
作者:Jan C. Schöneboom、Stefan Groetsch、Manfred Christl、Bernd Engels
DOI:10.1002/chem.200305000
日期:2003.10.6
In the case of 8, the allene structure 8 a is more stable than the zwitterionic form 8 b by only approximately 1 kcal mol(-1). These results suggest a high reactivity of 6 and 8 towards nucleophiles and explains the behaviour of 7. In addition to the ground states, the low-lying excited states of 6 and 8 were considered, which are represented by the diradicals 6 c and 8 c and, as singlets, lie above
用KOtBu处理3-溴-1-甲基-1,2-二氢喹啉(9)和[18] crown-6在呋喃或苯乙烯中的溶液,然后水解,得到1-甲基-1,2-二氢喹啉的混合物(10)和1-甲基-2-喹诺酮(11)。如果反应在[D(8)] THF中进行,并立即通过NMR光谱分析混合物,则表明2-叔丁氧基-1-甲基-1,2-二氢喹啉(17)是10和10的前体。 11. 17的结构是标题为cycloallene 7的证据,该化合物是通过β消除溴化氢而从9衍生而来的,并被KOtBu捕集,生成17的速度如此之快,以至于7与呋喃或苯乙烯的环加成反应无法竞争。由于与大多数已知的六元环状亚丙基相比,这种反应性是不同寻常的,因此我们对8的量子化学计算进行了计算,这是7的母体化合物 以及相应的异吡啶6来评估这些物种的电子性质。基态6不再是丙二烯(6a),而是两性离子6b。在8的情况下,丙二烯结构8a比两性离子形式8b稳定仅约1kcal