73854-04-3Relevant academic research and scientific papers
Tridentate nitrogen phosphine ligand containing arylamine NH as well as preparation method and application thereof
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Paragraph 0095-0102; 0105-0109, (2021/06/26)
The invention discloses a tridentate nitrogen phosphine ligand containing arylamine NH as well as a preparation method and application thereof, and belongs to the technical field of organic synthesis. The tridentate nitrogen phosphine ligand disclosed by the invention is the first case of tridentate nitrogen phosphine ligand containing not only a quinoline amine structure but also chiral ferrocene at present, a noble metal complex of the type of ligand shows good selectivity and extremely high catalytic activity in an asymmetric hydrogenation reaction, meanwhile, a cheap metal complex of the ligand can also show good selectivity and catalytic activity in the asymmetric hydrogenation reaction, and is very easy to modify in the aspects of electronic effect and space structure, so that the ligand has huge potential application value. A catalyst formed by the ligand and a transition metal complex can be used for catalyzing various reactions, can be used for synthesizing various drugs, and has important industrial application value.
One-Pot Transformation of Ketoximes into Optically Active Alcohols and Amines by Sequential Action of Laccases and Ketoreductases or ω-Transaminases
Correia Cordeiro, Raquel S.,Ríos-Lombardía, Nicolás,Morís, Francisco,Kourist, Robert,González-Sabín, Javier
, p. 1272 - 1277 (2019/01/24)
An enzymatic one-pot process for asymmetric transformation of prochiral ketoximes into alcohols or amines was developed by sequential coupling of a laccase-catalyzed deoximation either with a ketone reduction (ketoreductase, KRED) or bioamination (ω-transaminase, ω-TA) in aqueous medium. An accurate selection of biocatalysts provided the corresponding products in excellent enantiomeric excesses and overall conversions ranging from 83 to >99 % for alcohols and 70 to >99 % for amines. Likewise, the employment of exclusively 1 % (w/w) of Cremophor, a polyethoxylated castor oil, as co-solvent enabled to reach concentrations up to 100 mM in the chiral alcohols cascade.
Towards practical earth abundant reduction catalysis: Design of improved catalysts for manganese catalysed hydrogenation
Widegren, Magnus B.,Clarke, Matthew L.
, p. 6047 - 6058 (2019/11/14)
Manganese catalysts derived from tridentate P,N,N ligands can be activated easily using weak bases for both ketone and ester hydrogenations. Kinetic studies indicate the ketone hydrogenations are 0th order in acetophenone, positive order in hydrogen and 1st order in the catalyst. This implies that the rate determining step of the reaction was the activation of hydrogen. New ligand systems with varying donor strength were studied and it was possible to make the hydrogen activation significantly more efficient; a catalyst displaying around a 3-fold increase in initial turn-over frequencies for the hydrogenation of acetophenone relative to the parent system was discovered as a result of these kinetic investigations. Ester hydrogenations and ketone transfer hydrogenation (isopropanol as reductant) are first order for both the substrate and catalysts. Kinetic studies also gained insight into catalyst stability and identified a working range in which the catalyst is stable throughout the catalytic reaction (and a larger working range where high yields can still be achieved). The new more active catalyst, combining an electron-rich phosphine with an electron-rich pyridine is capable of hydrogenating acetophenone using as little as 0.01 mol% catalyst at 65 °C. In all, protocols for reduction of 21 ketones and 15 esters are described.
Programming cascade reactions interfacing biocatalysis with transition-metal catalysis in: Deep Eutectic Solvents as biorenewable reaction media
Cicco, Luciana,Ríos-Lombardía, Nicolás,Rodríguez-álvarez, María J.,Morís, Francisco,Perna, Filippo M.,Capriati, Vito,García-álvarez, Joaquín,González-Sabín, Javier
supporting information, p. 3468 - 3475 (2018/08/07)
The first application of Deep Eutectic Solvents (DESs) in the asymmetric bioreduction of ketones has been accomplished for purified ketoreductases (KREDs). The performance of the biocatalysts was enhanced by increasing the percentage of neoteric solvent in DES-buffer mixtures. At a buffer content of 50% (w/w) and even 20% (w/w), the combination of either choline chloride (ChCl)/glycerol (Gly) (1:2) or ChCl/sorbitol (1:1) proved to be most effective for achieving up to >99% conversion and up to >99% enantiomeric excess of the corresponding secondary alcohols. Moreover, this reaction medium was used to perform the first example of a chemoenzymatic cascade process in DES-buffer mixtures, namely the ruthenium-catalysed isomerisation of racemic allylic alcohols coupled with a further enantioselective bioreduction, in both sequential and concurrent modes.
Osmium(II)/R-pybox vs ruthenium(II)/R-pybox complexes in the catalytic asymmetric transfer hydrogenation of arylketones
de Julián, Eire,Fernández, Nuria,Díez, Josefina,Lastra, Elena,Gamasa, M. Pilar
, p. 75 - 86 (2018/07/25)
The reaction of the complexes trans-[RuCl2(η2-C2H4){(S,S)-iPr-pybox}] (1a) and trans-[RuCl2(η2-C2H4){(R,R)-Ph-pybox}] (1b) with nitrogen heterocyclic ligands, provide the complexes trans-[RuCl2(L)(R-pybox)] (L = py (3a,b), 3-Br-py (4a,b), isoquinoline (5a,b), pyrazine (6a,b), 1-methylimidazole (7a,b), 1-benzylimidazole (8a,b), pyrazole (9a,b), 3-methylpyrazole (10a,b), and 1H-1,2,4-triazole (11a,b)). The complexes trans-[OsCl2(L){(S,S)-iPr-pybox}] (L = py (12), 3-Br-py (13), 3-CN-py (14), 3-MeO-py (15), 3-NO2-py (16), 4-CN-py (17), 4-MeO-py (18), isoquinoline (19), 1-methylimidazole (20), 1-benzylimidazole (21), pyrazole (22)) have been similarly synthesized by the substitution of ethylene from the precursor complex trans-[OsCl2(η2-C2H4){(S,S)-iPr-pybox}] (2) by the corresponding N-donor ligand in refluxing toluene. Moreover, the dinuclear complexes [(RuCl2{(S,S)-iPr-pybox})2(μ-N,N-C4H4N2)] (23a), [(RuCl2{(R,R)-Ph-pybox})2(μ-N,N-C4H4N2)] (23b) and [(OsCl2{(S,S)-iPr-pybox})2(μ-N,N-C4H4N2)] (24) have been prepared by the reaction of the complexes 1 and 2 with pyrazine (1:0.5 M ratio for 23 and 1:1.5 for 24). The structure of the complexes 9a, 12, 23a and 24 has been determined by single-crystal X-ray diffraction analysis. The ruthenium 3a,b, 6a and 10a,b and osmium complexes 12–22 and 24 have been assayed as catalysts for the asymmetric transfer hydrogenation reaction. Among them, the osmium complexes 12, 15, 16, 18 and 24 have proven more efficient in the reduction of a variety of aromatic ketones affording the (R)-benzylalcohols with very high conversion and moderate enantioselectivity up to 73% e.e.
Central-to-Helical-to-Axial-to-Central Transfer of Chirality with a Photoresponsive Catalyst
Pizzolato, Stefano F.,?tacko, Peter,Kistemaker, Jos C. M.,Van Leeuwen, Thomas,Otten, Edwin,Feringa, Ben L.
supporting information, p. 17278 - 17289 (2019/01/04)
Recent advances in molecular design have displayed striking examples of dynamic chirality transfer between various elements of chirality, e.g., from central to either helical or axial chirality and vice versa. While considerable progress in atroposelective synthesis has been made, it is intriguing to design chiral molecular switches able to provide selective and dynamic control of axial chirality with an external stimulus to modulate stereochemical functions. Here, we report the synthesis and characterization of a photoresponsive bis(2-phenol)-substituted molecular switch 1. The unique design exhibits a dynamic hybrid central-helical-axial transfer of chirality. The change of preferential axial chirality in the biaryl motif is coupled to the reversible switching of helicity of the overcrowded alkene core, dictated by the fixed stereogenic center. The potential for dynamic control of axial chirality was demonstrated by using (R)-1 as switchable catalyst to direct the stereochemical outcome of the catalytic enantioselective addition of diethylzinc to aromatic aldehydes, with successful reversal of enantioselectivity for several substrates.
New chiral amino alcohol ligands for catalytic enantioselective addition of diethylzincs to aldehydes
Sappino, Carla,Mari, Alessandra,Mantineo, Agnese,Moliterno, Mauro,Palagri, Matteo,Tatangelo, Chiara,Suber, Lorenza,Bovicelli, Paolo,Ricelli, Alessandra,Righi, Giuliana
, p. 1860 - 1870 (2018/03/23)
A study aimed at the synthesis and structure optimization of new, efficient, optically active β-amino alcohol ligands with a structure suitable for immobilization on magnetite nanoparticles has been carried out. The optimized homogeneous amino alcohol catalysts 13a and 13b, the chirality of which arises from the Sharpless epoxidation of suitable allyl alcohols, were tested by employing the well-established enantioselective amino alcohol-promoted addition of diethylzinc to benzaldehyde, giving the corresponding benzyl alcohol with nearly quantitative yield and ee = 95%. Then, their broad applicability as chiral catalysts was evaluated by carrying out the same reaction on a family of aldehydes, including variously substituted aromatic ones as well as an aliphatic analogue. The results have confirmed the validity of the fine-tuning process performed on ligands 13a and 13b. In fact, both exhibited excellent catalytic activity as demonstrated by the chemical yields and ee obtained from all the tested aldehydes, almost independent of the position and type of substitution in the aromatic ring.
Highly enantioselective asymmetric reactions involving zinc ions promoted by chiral aziridine alcohols
Jarzyński, Szymon,Utecht, Greta,Le?niak, Stanis?aw,Rachwalski, Micha?
, p. 1774 - 1779 (2017/11/16)
Enantiomerically pure, chiral secondary and tertiary aziridine alcohols (including the aziridine analogue of ProPhenol—AziPhenol) have proven to be highly effective catalysts for enantioselective asymmetric reactions in the presence of zinc ions, including arylation of aromatic aldehydes, epoxidation of chalcone and addition of diethylzinc to aldehydes, leading to the desired chiral products in high chemical yields (up to 90%) and with ee's up to 90%. A higher catalytic activity of Prophenol-type bis(aziridine alcohol) in the aforementioned asymmetric transformations has been demonstrated.
From a Sequential to a Concurrent Reaction in Aqueous Medium: Ruthenium-Catalyzed Allylic Alcohol Isomerization and Asymmetric Bioreduction
Ríos-Lombardía, Nicolás,Vidal, Cristian,Liardo, Elisa,Morís, Francisco,García-álvarez, Joaquín,González-Sabín, Javier
supporting information, p. 8691 - 8695 (2016/07/21)
The ruthenium-catalyzed redox isomerization of allylic alcohols was successfully coupled with the enantioselective enzymatic ketone reduction (mediated by KREDs) in a concurrent process in aqueous medium. The overall transformation, formally the asymmetric reduction of allylic alcohols, took place with excellent conversions and enantioselectivities, under mild reaction conditions, employing commercially and readily available catalytic systems, and without external coenzymes or cofactors. Optimization resulted in a multistep approach and a genuine cascade reaction where the metal catalyst and biocatalyst coexist from the beginning.
Chiral N-heterocyclic carbene iridium catalyst for the enantioselective hydrosilane reduction of ketones
Manabe, Yoshiki,Shinohara, Kanako,Nakamura, Hanako,Teramoto, Hiro,Sakaguchi, Satoshi
, p. 138 - 145 (2016/06/15)
Enantioselective reduction of ketones with (EtO)2MeSiH catalyzed by an in-situ generated N-heterocyclic carbene (NHC) Ir complex at room temperature has been developed. A series of benzimidazolium salts were synthesized and screened in the asymmetric hydrosilylation reaction. As a result, propiophenone was efficiently reduced by the combined catalytic system of [IrCl(cod)]2 and NHC-Ag complex derived from N-(1-naphthalenylmethyl)-substituted benzimidazolium salt L12, affording the corresponding alcohol in 92% yield and with 92% ee. Moreover, the evaluation of an Ir catalyst precursor showed that cationic [Ir(cod)2]BF4 complex could be used. Furthermore, the introduction of a chiral hydroxyamide side arm into the benzimidazolium salt was critical for the successful design of the NHC ligand.
