[Rh2(MEPY)4] and [BiRh(MEPY)4]: Convenient Syntheses and Computational Analysis of Strikingly Dissimilar Siblings |
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Authors: | Lorenz E. Löffler Michael Buchsteiner Lee R. Collins Fabio P. Caló Santanu Singha Alois Fürstner |
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Affiliation: | 1. Max-Planck-Institut für Kohlenforschung, DE-45470 Mülheim/Ruhr, Germany These authors contributed equally.;2. Max-Planck-Institut für Kohlenforschung, DE-45470 Mülheim/Ruhr, Germany |
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Abstract: | [Rh2(MEPY)4] is a versatile catalyst for asymmetric synthesis but its preparation requires purification by chromatography on surface-modified silica. A higher yielding procedure based on a more convenient work-up is presented herein. Moreover, a much improved method for the preparation of [BiRh(OTfa)4] is described, which makes this heterobimetallic complex readily available. Subsequent exchange of the trifluoroacetate ligands opens access to a so far underappreciated family of (chiral) paddlewheel complexes. While [BiRh] complexes comprising four carboxylate ligands are highly adequate for intermolecular asymmetric cyclopropanation reactions, [BiRh(MEPY)4] as the heterobimetallic cousin of [Rh2(MEPY)4] was found to be surprisingly unreactive; DFT calculations uncover the reasons for this inertia. |
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Keywords: | bismuth carbenes cyclopropanation heterobimetallic complexes rhodium |
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