Cooperative Effects between Chiral Cpx -Iridium(III) Catalysts and Chiral Carboxylic Acids in Enantioselective C-H Amidations of Phosphine Oxides.

Abstract

An enantioselective C-H amidation of phosphine oxides by using an iridium(III) catalyst bearing an atropchiral cyclopentadienyl (Cpx ) ligand is reported. A very strong cooperative effect between the chiral Cpx ligand and a phthaloyl tert-leucine enabled the transformation. Matched-mismatched cases of the different acid enantiomers are shown. The amidated P-chiral arylphosphine oxides are formed in yields of up to 95 % and with excellent enantioselectivities of up to 99:1 er. Enantiospecific reduction provides access to valuable P-chiral phosphorus(III) compounds.