Copper-catalyzed cycloaddition of alkynes with 4-bromosydnones provides a convenient, mild, and regioselective method for the synthesis of a wide range of bromopyrazoles. The broad functional group tolerance of the cycloaddition reaction and further palladium-catalyzed cross-coupling reactions allowed the preparation of polyfunctionalized 1,4,5-pyrazoles that are otherwise difficult to obtain by conventional
铜与4-
溴丁酮的
铜催化环加成反应为合成多种
溴吡唑提供了一种方便,温和且区域选择性的方法。环加成反应和进一步的
钯催化的交叉偶联反应具有宽泛的官能团耐受性,因此可以制备多官能化的1,4,5-
吡唑,否则很难通过常规方法获得。