On the reaction of prop-2-enylidenetriphenylphosphorane derivatives. Novel synthesis of the azulene ring system
作者:Tohru Takayasu、Makoto Nitta
DOI:10.1039/a605581h
日期:——
Reaction of prop-2-enylidenetriphenylphosphorane derivatives with
several tropones has been studied in an attempt to provide a short new
route to the azulene ring system.
(2-Ethoxyprop-2-enylidene)triphenylphosphorane 4 reacts with 2-chloro-,
2-methoxy- and 2,3,5,7-tetrachlorotropones 7a–c to give azulene
derivatives 8 and 9 in moderate yields. On the other hand, reaction of
[2-ethoxy-3-(ethoxycarbonyl)prop-2-enylidene]triphenylphosphorane 6 with
tropones 7a,c results in the formation of azulene esters 10 and 11 in
low yields, whilst that with tropone 7b gives no azulene and substrate
7b is recovered. In order to gain insight into the mechanistic pathways,
reaction of phosphoranes 4 and 6 with deuteriated tropones 14a,b which
are the corresponding trideuteriated derivatives of compounds 7a,b, have
also been studied. Furthermore, compound 4 reacts also with
5-(dimethylaminomethylene)cyclopenta-1,3-dienecarbaldehyde 33 to give
6-ethoxyazulene 37 in moderate yield.
丙-2-烯基三苯基正膦衍生物与
对几种托酮进行了研究,试图提供一个简短的新方法
通向甘菊环系统的路线。
(2-乙氧基丙-2-亚乙烯基)三苯基正膦 4 与 2-氯-,
2-甲氧基- 和 2,3,5,7-四氯托酮 7a–c 得到甘菊环
衍生物8和9的产率适中。另一方面,反应
[2-乙氧基-3-(乙氧基羰基)丙-2-亚乙烯基]三苯基正膦 6 与
托酮 7a,c 导致形成甘菊酯 10 和 11
产率低,而使用托品酮 7b 则不产生甘菊环和底物
7b被恢复。为了深入了解机制途径,
正膦 4 和 6 与氘化托酮 14a,b 的反应
是化合物 7a,b 相应的三氘代衍生物,有
也被研究过。此外,化合物4还与
5-(二甲基氨基亚甲基)环戊-1,3-二烯甲醛 33 得到
6-乙氧基甘菊环37,产率中等。