A facile and convenient strategy for the assembly of N-arylated heterocycles has been demonstrated using a MnCl2.4H2O/trans-1,2-diaminocyclohexane catalyst and K3PO4 as the base in water.
A manganese/copper bimetallic catalyst for C–N coupling reactions under mild conditions in water
作者:Yong-Chua Teo、Fui-Fong Yong、Gina Shiyun Lim
DOI:10.1016/j.tetlet.2011.10.128
日期:2011.12
An efficient and convenient bimetallic MnF2/CuI catalyst in combination with trans-1,2-diaminocyclohexane has been developed for the cross-coupling of nitrogen heterocycles with aryl halides in water at moderate temperature. A variety of nitrogen nucleophiles including pyrazole, 7-azaindole, indazole, indole, pyrrole and imidazole afforded the corresponding products in moderate to good yields (up to
Abstract A simple and efficient strategy for the C–N cross-coupling of indazole with a variety of substituted arylbromides is reported. Under the optimized conditions, a broad scope of N-arylated products were obtained in good to excellent yields (up to 87%) under the ligand-free conditions.
A simple and practical protocol has been developed for the cross-coupling of azoles and aryl iodides under ligand-free copper(I) oxidecatalyzed conditions in water. The protocol uses tetrabutylammonium bromide (TBAB) as the phase-transfer catalyst, and water as the solvent, and shows good tolerance towards various functional groups.
A mild and regioselective Ullmann reaction of indazoles with aryliodides has been developed as a general method for the synthesis of 1-aryl-1H-indazoles. Water was used as the solvent wherein Tween 20 (2% w/w) was added to form aqueous micelles to improve solubility of starting materials and accelerate reaction rate. This aqueous protocol allows the Ullmann reaction to proceed at a mild temperature