An efficient novel synthesis of β-(azuleno[1,2-b]benzothienyl)- and β-(azuleno[2,1-b]benzothienyl)-α,β-unsaturated ketones by the tropylium ion-mediated intramolecular furan ring-opening reaction and X-ray investigation of methyl ketone derivative1
作者:Kimiaki Yamamura、Yuuko Houda、Masao Hashimoto、Takatomo Kimura、Makoto Kamezawa、Takehiko Otani
DOI:10.1039/b401579g
日期:——
Intramolecular reaction of 2-tropylio-3-(5-substituted 2-furyl)benzothiophenes (3), prepared from the corresponding 2-cycloheptatrienyl-3-(5-substituted 2-furyl)benzothiophenes (2), afforded the beta-(azuleno[1,2-b]benzothienyl)-alpha,beta-unsaturated ketones (4), which are otherwise difficult to obtain, in moderate yields. The reaction involves a ring-opening process of the furan ring by intramolecular
由相应的2-环庚三烯基-3-(5-取代的2-呋喃基)苯并噻吩(2)制得的2-对甲苯基-3-(5-取代的2-呋喃基)苯并噻吩(3)的分子内反应得到β-(阿苏莱诺[1,2-b]苯并噻吩基)-α,β-不饱和酮(4),否则难以获得,收率适中。该反应涉及通过将对转鎓离子分子内攻击到呋喃环的2-位上的呋喃环的开环过程。相似地,尽管在较低的产量。在X射线结构分析的基础上,讨论了甲基酮衍生物8a的分子和晶体结构。