Ligands for Iridium-catalyzed Asymmetric Hydrogenation of Challenging Substrates

Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland 

Enantioselective homogeneous hydrogenation catalyzed by chiral transition metal complexes is one of the most well established transformations in asymmetric synthesis [1]. Excellent enantioselectivities have been achieved in the hydrogenation of a wide range of substrates, often with very low catalyst loadings. High reliability, mild reaction conditions, and perfect atom economy are further attractive attributes of this method. In particular complexes based on Ru or Rh have found broad application in industrial processes [1] and the impact of these catalysts has been recognized by the Nobel Prize awarded to Ryoji Noyori and William S. Knowles in 2001 [2]. 

In this chapter, we focus on a more recent direction in asymmetric hydrogenation, the development of Ir catalysts based on heterobidentate ligands, which have considerably enhanced the substrate scope for this transformation. In particular, the major ligand classes and the underlying design principles as well as the special features and selected applications of these catalysts are discussed. We also dwell on recent mechanistic 

Ligand Design in Metal Chemistry Reactivity and Catalysis, First Edition. Edited by Mark Stradiotto and Rylan J. Lundgren. 

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Ligands for Iridium-catalyzed Asymmetric Hydrogenation of Challenging Substrates... 

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