A Continuously Regenerable Chiral Ammonia Borane for Asymmetric Transfer Hydrogenations

Zhou, Qiwen; Meng, Wei; Yang, Jing; Du, Haifeng

doi:10.1002/ange.201806877

Cited by 16 publications

(1 citation statement)

References 58 publications

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“…We have previously prepared a number of N4 ligands including aminobenzimidazole N4 ligands for the catalytic oxidation reactions [29–33] . In addition, ammonia‐borane (NH 3 ⋅ BH 3 , AB) has been shown to be a promising transfer hydrogenation agent [34–37] . In 2016, Liu and coworkers developed a cobalt‐catalyzed transfer hydrogenation of alkyne to produce Z ‐ and E ‐alkenes with NH 3 ⋅ BH 3 as the hydrogen source.…”

Section: Introductionmentioning

confidence: 99%

Cobalt(II)‐Catalyzed Transfer Hydrogenation of Simple Alkenes

Tian

Xu²,

Sun

2022

Adv Synth Catal

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Several cobalt(II) complexes supported by tetradentate aminobenzimidazole (N4) ligands and a tridentate nitrogen (N3) ligand have been prepared and characterized. X‐ray crystallographic analysis indicates that the cobalt complex of BPMB (BPMB=1,2‐bis((S)‐2‐(1‐methyl‐1H‐benzo[d]imidazol‐2‐yl) pyrrolidin‐1‐yl)ethane) ligand shows a distorted octahedral configuration. These cobalt(II) complexes can catalyze the transfer hydrogenation reaction of simple olefins with ammonia borane as a hydrogen source, and a variety of terminal olefins can be reduced to corresponding alkanes in good to excellent yields under mild reaction conditions. Note that Co−N3 complex provides an inferior outcome than those of Co−N4 complexes.

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Section: Introductionmentioning

confidence: 99%

Cobalt(II)‐Catalyzed Transfer Hydrogenation of Simple Alkenes

Tian

Xu²,

Sun

2022

Adv Synth Catal

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Catalytic Mechanism Study on the 1,2‐ and 1,4‐Transfer Hydrogenation of Ketimines and β‐Enamino Esters Catalyzed by Axially Chiral Biscarboline‐Based Alcohols

Dong

Wang

et al. 2019

Adv Synth Catal

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Axial N-O alcohols, which have two large carboline moieties connected to the axis were synthesized and used in catalytic enantioselective 1,2-and 1,4-transfer hydrogenations of total 26 ketimines and β-enamino esters. Excellent levels of enantioselectivity ranging from 91% to 99% were achieved by using catalyst (aS)-2oxide. Interestingly, a mixture of (aS)-(S)-3,3'-bis ((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9'dimethyl- 9H,9'H-[1,1'-bipyrido[3,4-b]indole] 2oxide and (aR)-(S)-3,3'-bis((S)-2-(hydroxymethyl) pyrrolidine-1-carbonyl)-9,9'-dimethyl-9H,9'H-[1,1'bipyrido[3,4-b]indole] 2-oxide was also able to provide high enantioselectivities up to 95% that is the same as that using pure (aS)-(S)-3,3'-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9'dimethyl- 9H,9'H-[1,1'-bipyrido[3,4-b]indole] 2oxide. A plausible catalytic mechanism was suggested and total four kinds of transition states (TS) including almost 60 TS structures were investigated using density functional theory (DFT) with different basis sets such as 6-311G(2d,p). The predicted activation energy data are consistent with the experimental results.

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Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration

et al. 2020

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A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H 2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene > diphenylmethanimine > benzaldehyde > azobenzene > nitrobenzene > quinoline > acetophenone > benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc) 2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D 2 O and HBPin via in situ HD generation and discrimination.

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A Continuously Regenerable Chiral Ammonia Borane for Asymmetric Transfer Hydrogenations

Cited by 16 publications

References 58 publications

Cobalt(II)‐Catalyzed Transfer Hydrogenation of Simple Alkenes

Cobalt(II)‐Catalyzed Transfer Hydrogenation of Simple Alkenes

Catalytic Mechanism Study on the 1,2‐ and 1,4‐Transfer Hydrogenation of Ketimines and β‐Enamino Esters Catalyzed by Axially Chiral Biscarboline‐Based Alcohols

Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration

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