1,2,3-Triazol-5-ylidene–palladium complex catalyzed Mizoroki–Heck and Sonogashira coupling reactions

The bis-1,4-dimesityl-1,2,3-triazol-5-ylidene–palladium complex (1a) successfully catalyzes the Mizoroki–Heck and Sonogashira coupling reactions with aryl bromides to give the corresponding alkenes and alkynes, respectively, in good to excellent yields. In the Mizoroki–Heck reaction, electron-rich, electron-poor, and functionalized aryl bromides and alkenes are tolerated, while the substrates are limited to electron-poor aryl halides in the Sonogashira coupling reaction. The palladium complex also catalyzes cross-coupling reactions with aryl chlorides to give higher yields of products than does the bis-IMes–Pd complex analogue (2), under specific conditions.