Synthesis of Josiphos-Type Bisphospholane Ligands

Bisphospholane Josiphos-type ligands were synthesized in high yields employing electrophilic and nucleophilic phospholane synthons. Full characterization data including solid-state structures of the diastereomeric ligands are reported. These ligands resulted in active and enantioselective iridium catalysts for the asymmetric hydrogenation of imines. Pronounced cooperative effects of the chiral elements within the ligand structure were observed and enantioselectivities of up to 74% ee were achieved.