- Highly Active Cooperative Lewis Acid—Ammonium Salt Catalyst for the Enantioselective Hydroboration of Ketones
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Enantiopure secondary alcohols are fundamental high-value synthetic building blocks. One of the most attractive ways to get access to this compound class is the catalytic hydroboration. We describe a new concept for this reaction type that allowed for exceptional catalytic turnover numbers (up to 15 400), which were increased by around 1.5–3 orders of magnitude compared to the most active catalysts previously reported. In our concept an aprotic ammonium halide moiety cooperates with an oxophilic Lewis acid within the same catalyst molecule. Control experiments reveal that both catalytic centers are essential for the observed activity. Kinetic, spectroscopic and computational studies show that the hydride transfer is rate limiting and proceeds via a concerted mechanism, in which hydride at Boron is continuously displaced by iodide, reminiscent to an SN2 reaction. The catalyst, which is accessible in high yields in few steps, was found to be stable during catalysis, readily recyclable and could be reused 10 times still efficiently working.
- Titze, Marvin,Heitk?mper, Juliane,Junge, Thorsten,K?stner, Johannes,Peters, René
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p. 5544 - 5553
(2021/02/05)
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- HYDROGENATION OF ALDEHYDE OR KETONE COMPOUNDS WITH FE/TRIDENTATE LIGANDS COMPLEXES
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The present invention relates to the field of catalytic hydrogenation and, more particularly, to the use of Fe complexes with tridentate ligands, having one amino or imino coordinating group and two phosphino coordinating groups, in hydrogenation processes for the reduction of ketones or aldehydes, into the corresponding alcohol or diol, respectively.
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Page/Page column 25-27
(2017/01/02)
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- HYDROGENATION OF ESTERS WITH FE/TRIDENTATE LIGANDS COMPLEXES
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The present invention relates to the field of catalytic hydrogenation and, more particularly, to the use of Fe complexes with tridentate ligands, having one amino or imino coordinating group and two phosphino coordinating groups, in hydrogenation processes for the reduction of ketones, aldehydes, esters or lactones into the corresponding alcohol or diol, respectively.
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Page/Page column 17; 18
(2015/07/07)
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- HYDROGENATION OF ESTERS OR CARBONYL GROUPS WITH PHOSPHINO-OXIDE BASED RUTHENIUM COMPLEXES
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The present invention relates to the field of catalytic hydrogenation and, more particularly, to the use of specific ruthenium catalysts or pre-catalysts in hydrogenation processes for the reduction of ketones, aldehydes, esters or lactones into their corresponding alcohols or diols respectively. The preferred catalysts are ruthenium complexes comprising a ligand of the type (N—N) type and a ligand of the type (P—PO).
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Page/Page column 15; 16
(2011/08/08)
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