Upgrading Carbazolyl-Derived Phosphine Ligands Using RhI-Catalyzed PIII-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 out-performed common commercial or unfunctionalized phosphines and their precursors in the Pd-catalyzed carbon dioxide-fixation reactions with propargylic amines.

Automated summary

We report on an Rh(I)-catalyzed C-H bond alkylation of PhenCarPhos and related phosphine ligands with alkenes. The C-H bond functionalization selectively occurs at the C1 position of the carbazolyl unit due to the presence of a trivalent phosphine directing group. This protocol offers a straightforward method to access a diverse library of C1-alkyl substituted PhenCarPhos, which exhibit superior performance compared to common commercial or unfunctionalized phosphines and their precursors in Pd-catalyzed carbon dioxide-fixation reactions with propargylic amines.