Nickel-catalyzed cross-coupling reactions of 4-mesylcoumarins with aryl halides: Facile synthesis of 4-substituted coumarins

摘要

A new and efficient nickel-catalyzed cross-coupling reaction between 4-mesylcoumarins and aryl halides was developed to give a number of 4-arylcoumarins in good yield under mild conditions. Unlike the previously reported coupling examples, this new method allows the direct cross-coupling of 4-mesylcoumarins with aryl- or vinyl halides in the NiCl2(PPh3)(2)/PPh3/Zn/toluene system. This has greatly facilitated the synthesis of biologically useful 4-substituted coumarins.