N,S-Chelating triazole-thioether palladium for the one-pot synthesis of biaryls

Abstract

In this work, for the one-pot two-step coupling reaction of aryl halides with bis(pinacol)diboron, we first applied a phosphorus-free N,S-chelated triazole sulfide palladium-catalyzed system. At the same time, we also carried out careful ligand design to explore the effect of the environment around the coordinating sulfur atom on the reaction. Experiments have shown that the N2-thioether substituted 1,2,3-triazlole palladium is an optimal catalyst The reaction could also reach up to quantitative yield in 4 h with only 1 mol% catalyst. Moreover, some low-activity aryl chlorides can also be coupled with bis(pinacolato)diboron under this catalytic system. We were able to obtain biaryls containing various functional groups in good to excellent yields.