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

• Published in: Angewandte Chemie International Edition Vol. 56; no. 47; pp. 15088 - 15092
• Main Authors: Jang, Yun‐Suk, Dieckmann, Michael, Cramer, Nicolai
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 20.11.2017
• Edition: International ed. in English
• Subjects: asymmetric catalysis; Carboxylic acids; Catalysis; Catalysts; chiral Cp ligand; C−H activation; Enantiomers; Iridium; Leucine; Ligands; Oxides; P-chirality; Phosphine; Phosphine oxide; Phosphorus
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201708440

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. Catalytic handshake: A cooperative effect between a chiral CpxIrIII complex and chiral carboxylic acid enables highly enantioselective C−H amidations of phosphine oxides with up to 99:1 e.r. Matched–mismatched pairs have a strong influence on the reactivity and selectivity.