A mechanically-activated chemoselective Heck coupling for the synthesis of 3-vinylindazoles has been developed with the aid of catalytic amounts of TBAB and NaBr as both dehalogenation restrainer and grinding auxiliary. After tuning of the chemical conditions and mechanical parameters, a series of non-activated 3-bromoindazoles and a broad scope of olefins worked well to give the corresponding coupling products in good to excellent yields. A further application of this protocol was performed in a two-step mechanochemical Heck/Migita cross coupling, which provided a highly efficient route for the synthesis of axitinib.
已开发出一种机械活化的化学选择性赫克偶联反应,用催化剂TBAB和NaBr作为去卤辅助剂和研磨辅助剂。在调整化学条件和机械参数后,一系列非活化的3-溴吲哚和广泛范围的烯烃表现良好,产率良好至优秀地给出了相应的偶联产物。该方案的进一步应用是在两步机械化学赫克/米吉塔交叉偶联反应中进行,为阿希替尼的合成提供了高效的途径。