The reaction of ortho-substituted aromatic azides with boron trichloride or trifluoride
作者:Piero Spagnolo、Paolo Zanirato
DOI:10.1039/p19880002615
日期:——
The reaction of borontrichloride or trifuoride with ortho-aryl, -diazoaryl, and -arylazoaryl phenyl azides in benzene at room temperature generally gives fused azoles in high yields. Treatment of 2-nitrophenyl azide with borontrichloride mainly affords chlorinated nitroanilines, whereas with borontrifluoride it gives N-o-nitrophenylaniline. In aromatic solvents at 60 °C in the presence of boron trifluoride–diethyl
N-[(2-Benzylideneamino)phenyl]-C-methylketenimines undergo intramolecular cyclization via two different reaction pathways, a [2+2] cycloaddition and a rare imino-ene reaction, to yield azeto[1,2-a]benznnidazoles and 2-(alpha-styryl)benzimidazoles, respectively. The results are interpreted in terms of a two-step mechanism involving two stereoisomeric conjugated betaines as intermediates. (C) 2002 Elsevier Science Ltd. All rights reserved.
Formal [4+2] intramolecular cycloaddition ketenimine-imine. Synthesis of benzimidazo[1,2-b]isoquinolines