Palladium-Catalyzed Amination of Aryl and Heteroaryl Tosylates at Room Temperature

摘要

Palladium-catalyzed animations of aryl halides occur under mild conditions with many catalysts, but animations of aryl sulfonates have been more challenging. The coupling of amines with aryl triflates has been known for many years, but aryl triflates are expensive to prepare and less stable to hydrolysis than other aryl sulfonates. Aryl tosylates are less expensive to prepare and are stable, crystalline solids. However, they are also less reactive. Although Suzuki and Kumada couplings of aryl tosylates at room temperature have been reported, only one coupling of amines with aryl tosylates at room temperature or with low catalyst loadings has been reported. Moreover, the coupling of amines with heteroaryl tosylates has not been reported, and the couplings of primary amines with aryl tosylates are rare.rnWe previously reported the oxidative addition of aryl tosylates at room temperature, but this fast addition did not lead to a general coupling with amines under similar conditions. Here, we report a new method to create a catalyst that couples aryl tosylates with primary alkylamines, arylamines, and N-H imines with fast rates and high turnover numbers under mild conditions. This process was achieved by combining the hindered Josiphos ligand CyPF-r-Bu (Table 1) with the unconventional Pd(0) precursor Pd[P(o-tol)_3]_2, which we show can be made in a practical manner.