Novel and efficient one-pot synthesis of azuleno[1,2-<i>b</i>]-benzothiophenic enones from the corresponding 2-cycloheptatrientyl-3-(2-furyl)benzothiophenes
2-Cycloheptatrienyl-3-(2-furyl)benzothiophenes, which are prepared by Stille coupling reaction of 2-cyclo-heptatrienyl-3-bromobenzothiophene with the 5-substituted 2-trimethylstannylfurans, react with triphenylmethyl tetrafluoroborate to give the correspondingazuleno[1,2-b]benzothiophenic enones in excellent yields.
通过2-环庚三烯基-3-溴苯并噻吩与5-取代的2-三甲基锡烷基呋喃的斯蒂勒偶联反应制得的2-环庚三烯基-3-(2-呋喃基)苯并噻吩与三苯基甲基四氟硼酸酯反应,得到相应的azuleno [1] ,2-2- b ]苯并噻吩的烯酮具有优异的收率。
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
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