[4.4.4]PROPELLAHEXAENE BY TRIPLE SHAPIRO DEGRADATION - STRUCTURAL AND ELECTRONIC-PROPERTIES OF THIS MAXIMALLY UNSATURATED HYDROCARBON AND CONSEQUENCES OF O-METHYLATION OF ITS [4.4.4]PROPELLATRIENETRIONE PRECURSORS
[4.4.4]PROPELLAHEXAENE BY TRIPLE SHAPIRO DEGRADATION - STRUCTURAL AND ELECTRONIC-PROPERTIES OF THIS MAXIMALLY UNSATURATED HYDROCARBON AND CONSEQUENCES OF O-METHYLATION OF ITS [4.4.4]PROPELLATRIENETRIONE PRECURSORS
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DOI：
10.1021/jo00292a040
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发表时间：
1990-03-02
影响因子：
3.6
通讯作者：
GLEITER, R
中科院分区：
文献类型：
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作者：
PAQUETTE, LA;LIANG, SW;GLEITER, R
制备了三烯三酮6和7，并将其转化为三苯磺酰腙，得到标题烃（5）。这些衍生物依次进行三重Shapiro降解。通过核磁共振谱和X射线晶体学分析证实了所得六烯的D3对称性质。当这个分子沿着其中心CC键观察时，其引人注目的螺旋桨状形状变得明显。热化学实验证实5是一种相当稳定的物质。涉及5及其较少不饱和类似物24和25的光电子光谱研究也进行了详细说明。通过这种方法，5的电子结构被证明是这样的，有没有cr-MO的在其高的lirMO的。5的MNDO计算预测中心键为1.61 A（实验值= 1.57 A）。还描述了详细描述7及其C&对称异构体6在尝试3倍O-甲基化时的命运的实验。在第一种情况下，主要产物恰好是3，6，9-三甲氧基菲（42）。6不会遇到Skills重排。相反，主要产物是二甲氧基烯酮39，其伴随有较少量的2，7-二甲氧基萘（40）。在进一步处理39时，在很大程度上发生裂解成40，尽管已经证明可以获得有限量的三甲氧基己烯41。6和7所表现出的化学反应的有趣分歧没有平行的。最后，报道了N-甲基三唑啉二酮与5，24和25的Diels-Alder反应的相对速率和立体化学过程（如果相关）。反应性顺序为5> 24> 25，六烯在室温下混合时瞬间消耗。24在其最初被MdR捕获期间所表现出的表面选择性在空间控制方面是最合理的。类似的考虑适用于44、45和5在它们与相同的亲二烯体的反应中遵循的途径。因此，轨道对称性的考虑似乎在这些过程中没有发挥重要作用。
The trienetriones 6 and 7 were prepared and transformed intotheir tris (phenylsulfonyl) hydrazonesto arrive at the title hydrocarbon (5). Thesederivatives were subjected in turn to triple Shapiro degradation. The D3 symmetric nature of the resulting hexaene was suggested by its NMR spectraand corroborated by X-ray crystallographic analysis. When this molecule is viewed down its central CC bond, its dramatic propeller-like shape is made evident. Thermochemical experiments established 5 to be a rather stablesubstance. Photoelectron spectroscopic studies involving 5 and its less unsaturated analogues24 and 25 are also detailed. By this means, the electronic structure of 5 was shown to be such that there are no cr-MO’s amid its high-lying ir MO’s. MNDO calculations for 5 predict the central bond to be 1.61 A (experimental value= 1.57 A). Also described are experiments detailing the fate of both 7 and its C& symmetric isomer 6 on attempted 3-fold O-methylation. In the first instance, the major product happens to be 3, 6, 9-trimethoxyphenanthrene (42). Skeletal rearrangement is not encountered with 6. Rather, the major product is dimethoxy enone 39, which is accompanied by lesser amounts of 2, 7-dimethoxynaphthalene (40). On further processing of 39, fragmentation to 40 occurs to a major extent, although it has proven possible to acquire limited amounts of the trimethoxy hexaene 41. The interesting divergence in chemical response exhibited by 6 and 7 has no parallel. Finally, the relative rates and stereochemical course (where relevant) of the Diels-Alder reaction of N-methyltriazolinedione (MTAD) with 5, 24, and 25 are reported. The reactivity order is 5> 24> 25, the hexaene being consumed instantaneously on mixing at room temperature. The facial selectivity exhibited by 24 during its initial capture by MTAD is best rationalizedin terms of steric control. Like considerations apply to the pathways followed by 44, 45 and 5 in their reactions with the same dienophile. Consequently, orbital symmetry considerations do not appear to play a major role in these processes.