Access to P- and Axially Chiral Biaryl Phosphine Oxides by Enantioselective Cpx IrIII -Catalyzed C-H Arylations

Abstract

An enantioselective C-H arylation of phosphine oxides with o-quinone diazides catalyzed by an iridium(III) complex bearing an atropchiral cyclopentadienyl (Cp^x ) ligand and phthaloyl tert-leucine as co-catalyst is reported. The method allows access to a) P-chiral biaryl phosphine oxides, b) atropo-enantioselective construction of sterically demanding biaryl backbones, and also c) selective assembly of axial and P-chiral compounds in excellent yields and diastereo- and enantioselectivities. Enantiospecific reductions provide monodentate chiral phosphorus(III) compounds having structures and biaryl backbones with proven importance as ligands in asymmetric catalysis.

Keywords: C−H activation; P-chirality; asymmetric catalysis; chiral Cp ligands; iridium.