Nickel‐Catalyzed Asymmetric Hydrogenation of α‐Substituted Vinylphosphonates and Diarylvinylphosphine Oxides

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(6)

Published: Dec. 12, 2022

Chiral α-substituted ethylphosphonate and ethylphosphine oxide compounds are widely used in drugs, pesticides, ligands. However, their catalytic asymmetric synthesis is still rare. Of the only hydrogenation methods available at present, all cases use rare metal catalysts. Herein, we report an efficient earth-abundant transition-metal nickel catalyzed affording corresponding chiral products with up to 99 % yield, 96 ee (enantiomeric excess) (99 ee, after recrystallization) 1000 S/C (substrate/catalyst); this also first study on of terminal olefins using a catalyst under hydrogen atmosphere. The mechanism was investigated via deuterium-labelling experiments calculations which indicate that two added atoms come from gas. Additionally, it believed reaction involves NiII rather than Ni0 cyclic process based weak attractive interactions between Ni olefin substrate.

Language: Английский

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Rhodium‐Catalyzed ON‐OFF Switchable Hydrogenation Using a Molecular Shuttle Based on a [2]Rotaxane with a Phosphine Ligand

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(15)

Published: Feb. 1, 2022

A novel pH-responsive molecular shuttle based on a [2]rotaxane with phosphine ligand has been designed and synthesized. In the rhodium-catalyzed hydrogenation of α,β-dehydroamino acid esters aryl enamides, ON/OFF-switchable catalysis was accomplished high ON/OFF ratios by adjusting movements rotaxane wheels located at catalyst terminals acid/base. Mechanistic studies using NMR spectroscopy quasi in situ X-ray photoelectron revealed that RhIII -hydride species are possibly formed H2 atmosphere when is OFF state. During reaction, heterolytic activation dihydrogen occurs interlocked dibenzylamine RhI catalytic center acting as frustrated Lewis pair. Subsequent homolytic splitting newly generates species. These findings show substrate-selective can be achieved OFF-state catalyst.

Language: Английский

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Rhodium‐Catalyzed ON‐OFF Switchable Hydrogenation Using a Molecular Shuttle Based on a [2]Rotaxane with a Phosphine Ligand

Angewandte Chemie, Journal Year: 2022, Volume and Issue: 134(15)

Published: Feb. 1, 2022

Abstract A novel pH‐responsive molecular shuttle based on a [2]rotaxane with phosphine ligand has been designed and synthesized. In the rhodium‐catalyzed hydrogenation of α,β‐dehydroamino acid esters aryl enamides, ON/OFF‐switchable catalysis was accomplished high ON/OFF ratios by adjusting movements rotaxane wheels located at catalyst terminals acid/base. Mechanistic studies using NMR spectroscopy quasi in situ X‐ray photoelectron revealed that Rh III ‐hydride species are possibly formed H 2 atmosphere when is OFF state. During reaction, heterolytic activation dihydrogen occurs interlocked dibenzylamine I catalytic center acting as frustrated Lewis pair. Subsequent homolytic splitting newly generates species. These findings show substrate‐selective can be achieved OFF‐state catalyst.

Language: Английский

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Nickel‐Catalyzed Asymmetric Hydrogenation of α‐Substituted Vinylphosphonates and Diarylvinylphosphine Oxides

Angewandte Chemie, Journal Year: 2022, Volume and Issue: 135(6)

Published: Dec. 12, 2022

Abstract Chiral α‐substituted ethylphosphonate and ethylphosphine oxide compounds are widely used in drugs, pesticides, ligands. However, their catalytic asymmetric synthesis is still rare. Of the only hydrogenation methods available at present, all cases use rare metal catalysts. Herein, we report an efficient earth‐abundant transition‐metal nickel catalyzed affording corresponding chiral products with up to 99 % yield, 96 ee (enantiomeric excess) (99 ee, after recrystallization) 1000 S/C (substrate/catalyst); this also first study on of terminal olefins using a catalyst under hydrogen atmosphere. The mechanism was investigated via deuterium‐labelling experiments calculations which indicate that two added atoms come from gas. Additionally, it believed reaction involves Ni II rather than 0 cyclic process based weak attractive interactions between olefin substrate.

Language: Английский

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