Synthesis of Binol-based diphosphinites bearing chiral phospholane units and their application in asymmetric catalysis |
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Authors: | Tim Hammerer Laurent Weisgerber Stefan Schenk Othmar Stelzer Ulli Englert Walter Leitner Giancarlo Franciò |
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Institution: | 1. Institut für Technische Chemie und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany;2. Fachbereich 9, Anorganische Chemie, Bergische Universität, Gaußstraße 20, 42097 Wuppertal, Germany;3. Institut für Anorganische Chemie, RWTH Aachen University, Landoldtweg 1, 52074 Aachen, Germany |
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Abstract: | New diphosphinite ligands based on atropoisomeric diol backbones and (R,R)-2,5-dimethylphospholane moieties have been prepared and fully characterised. For each ligand structure, both diastereomers have been synthesised. These ligands are available through a straightforward procedure in good yields. The solid state structures of two diastereomeric ligands are reported. These ligands have been applied to Rh-catalysed asymmetric hydrogenations and hydroformylations of C C bonds as well as in Ir-catalysed asymmetric hydrogenations of C N bonds. Turnover frequencies in the range of 10,000 h?1 and enantioselectivities of up to 98% ee have been achieved. The different chirality elements within the ligands led to marked cooperative effect in catalysis. Interestingly, there is no general privileged diastereomeric structure but rather a matched diastereomer for each application. |
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