Upgrading Carbazolyl-Derived Phosphine Ligands Using Rh^I‑Catalyzed P^III-Directed C–H Bond Alkylation for Catalytic CO₂‑Fixation Reactions

We report an Rh­(I)-catalyzed C–H bond alkylation of PhenCarPhos [N-(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.