Palladium-catalyzed selective Buchwald–Hartwig C–N coupling of chloroaryl triflates with amines

Abstract

The chemoselective Buchwald–Hartwig amination developed here showed that the reactivity of the Ar–Cl bond is higher than that of the Ar–OTf bond. Catalyzed by PdCl2/P(t-Bu)3, the reaction selectively aminated the Ar–Cl bond in an aryl system containing both Ar–Cl and Ar–OTf with moderate yield and excellent chemoselectivity, and the significant effect of additives was also found. With the aid of this methodology, we also efficiently synthesized a bicarbazole scaffold that can serve as a valuable precursor for alkaloids such as murrastifoline A&B.