Novel Metal-Free Hydrogenation of the Carbon−Carbon Double Bond in Azulenoid Enones by Use of Cycloheptatriene and Protic Acid
摘要:
[GRAPHICS]An efficient method for the hydrogenation of the carbon-carbon double bond in azulenoid and aromatic fused azulenoid enones without the use of hydrogen and a metal catalyst is reported. Treatment of a variety of azulenoid enones with cycloheptatriene and a protic acid in acetonitrile gave the corresponding, beta-azulenyl ketone derivatives in excellent to moderate yield. In this reaction, cycloheptatriene acts as a hydride donor.
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