Intramolecular meerwein reactions of the anthraquinone system. Synthesis, X-ray structural analysis and spectroscopic properties of anthra[9,1-<i>bc</i>:10,5-<i>b'c'</i>]tetrahydrodipyran derivatives
作者:H. Fritz、G. Rihs、P. Sutter、C. D. Weis
DOI:10.1002/jhet.5570180817
日期:1981.12
methylphosphonate as reaction medium. Compounds 5–18 were isolated as mixtures of diastereomers, some of which were separated by crystallization. Proof of structure and stereochemistry was obtained for some of the compounds by X-ray crystallographic analysis. The 1H- and 13C-nmr data provided further support. Surprisingly large chemical shift differences between some of the proton signals of isomers were observed
1,5-蒽醌双(硫酸氢二重氮)与充分活化的烯烃(如丙烯腈,丙烯酸酯,甲基丙烯腈及其酯,苯乙烯和α-甲基苯乙烯)的Meerwein反应产生了新杂环系统蒽的衍生物[9,1- bc:10,5 - b'c' ]-2,3,7,8-四氢双吡喃。通过使用甲基膦酸二甲酯作为反应介质,可以实现衍生物的分离并提高产率。化合物5-18是非对映异构体的混合物,其中一些通过结晶分离。通过X射线晶体学分析获得了某些化合物的结构和立体化学证明。的1 H-和13C-nmr数据提供了进一步的支持。尽管两个不对称中心通过键和空间相隔很远,但观察到异构体的某些质子信号之间的化学位移差异出乎意料地大。基于电荷转移络合物的氧化还原调节来解释其形成机理,其中脂族基团攻击蒽醌的氧原子。提出将这种新型反应分类为分子内Meerwein反应。