SPSiPs, A New Class of Biphosphine Ligands Based on SPSiOL with a Large Dihedral Angle

Here, we demonstrate the development and the synthetic applications of a novel class of diphosphine ligands (SPSiP) based on chiral spirosilabiindane diol (SPSiOL). Starting from SPSiOL, the biphosphine ligands could be readily prepared in three steps with high efficiency. This novel class of biphosphine ligands features rigid configuration, a large dihedral angle, a large P–M–P angle, and a long P–P distance, which might possess unique catalytic reactivities. The potentials of SPSiPs in asymmetric catalysis have also been preliminary disclosed by Rh-catalyzed asymmetric hydrogenation, Rh-catalyzed tandem hydrosilylation, and Pd-catalyzed asymmetric allylic alkylation.