Sterically Hindered Amination of Aryl Chlorides Catalyzed by a New Carbazolyl-Derived P,N-Ligand-Composed Palladium Complex

A family of 2-(9H-carbazol-9-yl)phenyl-based phosphine ligands were synthesized and their efficacy in promoting the steric hindered Buchwald-Hartwig amination was evaluated. In the presence of Pd(OAc) (2) (0.03-1.0 mol%) associated with the newly developed a carbazolyl-derived phosphine ligand, the synthesis of tetra- ortho -substituted diarylamines proceeded smoothly with excellent product yields (up to 99%). A remarkable result was obtained even for the coupling of highly sterically congested 2,6-diisopropylaniline and hindered 2-chloro-1,3,5-triisopropylbenzene (96% isolated yield). A possible decomposition pathway for the anthracenyl C-N coupling product is also reported.