Asymmetric Synthesis of Monodentate Phosphine Ligands Based on Chiral η⁶-Cr[arene] Templates

Optically active Cr-complexed arylphosphines are presented as a new class of chiral monodentate phosphine ligand for use in asymmetric catalysis. Asymmetric synthesis of the chiral phosphine ligands 9 is achieved in three steps from the achiral Cr[arene] precursor 3. A variety of ligand structures are accessed from a common synthesis intermediate. The utility of these phosphine ligands in asymmetric catalysis is highlighted in Pd(II)-catalyzed allylic alkylation reactions.