Upgrading Carbazolyl-Derived Phosphine Ligands Using Rh-Catalyzed P-Directed C-H Bond Alkylation for Catalytic CO-Fixation Reactions.

We report an Rh(I)-catalyzed C-H bond alkylation of PhenCarPhos [-(2-(diphenylphosphaneyl)phenyl)carbazole] and some congener phosphine ligands with alkenes. The C-H bond functionalization occurred exclusively at the C1 position of the carbazolyl unit because the trivalent phosphine acts as a directing group. This protocol provides straightforward access to a large library of C1-alkyl substituted PhenCarPhos, which outperformed common commercial or unfunctionalized phosphines and their precursors in the Pd-catalyzed carbon dioxide-fixation reactions with propargylic amines.