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Cooperative Effects between Chiral Cpx–Iridium(III) Catalysts and Chiral Carboxylic Acids in Enantioselective C−H Amidations of Phosphine Oxides |
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| Authors: | Yun-Suk Jang Dr Michael Dieckmann Prof Dr Nicolai Cramer |
| Institution: | 1. Laboratory of Asymmetric Catalysis and Synthesis, EPFL SB ISIC LCSA, BCH 4305, CH-1015 Lausanne, Switzerland;2. Laboratory of Asymmetric Catalysis and Synthesis, EPFL SB ISIC LCSA, BCH 4305, CH-1015 Lausanne, Switzerland
Current address: Syngenta Crop Protection AG, Schaffhauserstr., CH-4332 Stein, Switzerland |
| 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. |
| Keywords: | asymmetric catalysis C−H activation chiral Cp ligand iridium P-chirality |