Direct ortho-arylation of 2-arylbenzoxazoles via C–H activation
作者:Fan Yang、Yangjie Wu、Zhiwu Zhu、Junli Zhang、Yanan Li
DOI:10.1016/j.tet.2008.04.099
日期:2008.7
A new and highly regioselective arylation of 2-arylbenzoxazoles based on C–H activation has been developed. The results represent the first examples of palladium-catalyzeddirect ortho-arylation of 2-arylbenzoxazoles and also provide a facile route for the synthesis of complicated structures containing arylated benzoxazoles moieties.
substrates such as arylated benzoxazoles, acylated anilines, and pyridines has been developed. The arylation was performed in trifluoroacetic acid (TFA) under air by using PdCl2 as the catalyst with a lowcatalystloading of 1 mol %. And it was found for the first time that the addition of weak base K3PO4 to the acidic solvent could remarkably enhance the reaction rate. The arylated products were isolated