125875-26-5Relevant academic research and scientific papers
Synthesis and application of new iminopyridine ligands to enantioselective copper(II)-catalyzed Henry reaction
Solinas, Maurizio,Sechi, Barbara,Baldino, Salvatore,Chelucci, Giorgio
, p. 206 - 212 (2013)
Chiral iminopyridines obtained by reaction between a variety of chiral amines and pyridyl aldehydes or ketones were assessed as catalysts in the enantioselective Henry reaction between nitromethane and 2-methoxybenzaldehyde in the presence of copper(II) a
A facile circular dichroism protocol for rapid determination of enantiomeric excess and concentration of chiral primary amines
Nieto, Sonia,Dragna, Justin M.,Anslyn, Eric V.
, p. 227 - 232 (2010)
A protocol for the rapid determination of the absolute configuration and enantiomeric excess (ee) of α-chiral primary amines with potential applications in asymmetric reaction discovery has been developed. The protocol requires derivatization of α-chiral primary amines through condensation with pyridine carboxaldehyde to quantitatively yield the corresponding imine. The Cu1 complex with 2,2′-bis (diphenylphosphino)-l,l'- dinaphthyl (BINAP-Cu1) with the imine yields a metal-to-ligand charge-transfer (MLCT) band in the visible region of the circular dichroism (CD) spectrum upon binding. Diastereomeric hostguest complexes give CD signals of the same signs but different amplitudes, allowing for differentiation of enantiomers. Processing the primary optical data from the CD spectrum with linear discriminant analysis (LDA) allows for the determination of the absolute configuration and identification of the amines, and processing with a super-vised multilayer perceptron artificial neural network (MLP-ANN) allows for the simultaneous determination of the ee and concentration. The primary optical data necessary to determine the ee of unknown samples is obtained in two minutes per sample. To demonstrate the utility of the protocol in asymmetric reaction discovery, the ee values and concentrations for an asymmetric metal-catalyzed reaction are determined. The potential of the application of this protocol in high-throughput screening (HTS) of ee is discussed.
Structural elucidation of chiral (imino)pyridine/phosphine palladium(II) complexes and their applications as catalysts in methoxycarbonylation of styrene
Akiri, Saphan O.,Ngcobo, Nondumiso L.,Ogweno, Aloice O.,Ojwach, Stephen O.
, (2021/06/15)
Treatment of ligands (S)-1-phenyl-N-(1-(pyridin-2-yl)ethylidene)ethanamine (L1), (R)-1-phenyl-N-(1-(pyridin-2-yl)ethylidene)ethanamine (L2), (S)-1-phenyl-N-((pyridin-2-yl)methylene)ethanamine (L3), (R)-1-phenyl-N-((pyridin-2-yl)methylene)ethanamine (L4), (S)-N-(2-(diphenylphosphino)benzylidene)-1-phenylethanamine (L5), and (R)-N-(2-(diphenylphosphino)benzylidene)-1-phenylethanamine (L6) with [Pd(COD)Cl2] afforded the respective palladium complexes [Pd(L1)Cl2] (1), [Pd(L2)Cl2] (2), [Pd(L3)Cl2] (3), [Pd(L4)Cl2] (4), [Pd(L5)Cl2] (5) and [Pd(L6)Cl2] (6) in high yields. Solid-state structures of the complexes established N^N and N^P bidentate coordination mode of the ligands to give distorted square planar geometries. Complexes 1–6 displayed moderate catalytic activities in the methoxycarbonylation of styrene, to give predominantly branched esters of up to 95%. NMR spectroscopy studies pointed to possible decomposition of the active species, via ligand dissociation.
Structural, kinetics and mechanistic studies of transfer hydrogenation of ketones catalyzed by chiral (pyridyl)imine nickel(ii) complexes
Kumah, Robert T.,Tsaulwayo, Nokwanda,Xulu, Bheki A.,Ojwach, Stephen O.
supporting information, p. 13630 - 13640 (2019/09/30)
The chiral synthons (S-)-1-phenyl-N-(pyridine-2-yl)ethylidine)ethanamine (L1), (R-)-1phenyl-N-(pyridine-2-yl)ethylidine))ethanamine (L2) (S)-1-phenyl-N-(pyridine-2-yl methylene) ethanamine (L3), and (R)-1-phenyl-N-(pyridine-2-yl methylene) ethanamine (L4) were synthesized in good yields. Treatments of L1-L4 with NiBr2(DME) and NiCl2 precursor afforded dinuclear complexes [Ni2(L1)4-μ-Br2]NiBr4 (Ni1), [Ni2(L2)4-μ-Br2]NiBr4 (Ni2), [Ni2(L3)4-μBr2]Br2 (Ni3), [Ni2(L4)4-μ-Br2]NiBr4 (Ni4) and [Ni(L4)2Cl2] (Ni5). The identities of the compounds were established using NMR, FT-IR and EPR spectroscopy, mass spectrometry, magnetic moments, elemental analysis and single crystal X-ray crystallography. The dinuclear dibromide nickel complexes dissociate into mononuclear species in the presence of strongly coordinating solvents. Compounds Ni1-Ni5 displayed moderate catalytic activities in the asymmetric transfer hydrogenation (ATH) of ketones, but with low enantiomeric excess (ee%). Both mercury and substoichiometric poisoning tests pointed to the homogeneous nature of the active species with the partial formation of catalytically active Ni(0) nanoparticles. Low resolution mass spectrometry analyses of the intermediates supported a dihydride mechanistic pathway for the transfer of hydrogenation reactions.
Deciphering preferred geometries of pyridylmethylamines-based complexes: A robust strategy combining NMR, DFT and X-ray
Large, Benjamin,Meddeb, Maissa,Pucheta, José Enrique Herbert,Gaucher, Anne,Cordier, Marie,Gosmini, Corinne,Farjon, Jonathan,Auffrant, Audrey,Prim, Damien
supporting information, (2019/09/09)
The preparation of pyridylmethylamines (pma)-ZnBr2 and -CoBr2 complexes is described. Accurate structural informations in both solution and solid state have been obtained using an approach combining advanced NMR such as pure shift gr
Chiral Lithium Amido Zincates for Enantioselective 1,2-Additions: Auto-assembling Reagents Involving a Fully Recyclable Ligand
Rouen, Mathieu,Chaumont, Pauline,Barozzino-Consiglio, Gabriella,Maddaluno, Jacques,Harrison-Marchand, Anne
supporting information, p. 9238 - 9242 (2018/06/04)
A methodology consisting in carrying out enantioselective nucleophilic 1,2-additions (ee values up to 97 %) from cheap, easily accessible, and never described before, chiral lithium amido zincates is presented. These multicomponent reactants auto-assemble when mixing, in a 1:1 ratio, a homoleptic diorganozinc (R2Zn) with a chiral lithium amide (CLA). The latter, obtained after a single reductive amination, plays the role of the chiral inductor and is fully recoverable thanks to a simple acid–base wash, allowing being recycled and re-use without loss of stereochemical information.
Parallel screening of asymmetric bidentate ligands in zinc catalyzed transfer hydrogenation
Zaman, Tariq,Nasir, Habib,Bergin, Enda
, p. 85 - 90 (2014/05/06)
Development in the field of asymmetric catalysis is driven by the importance of stereochemically pure compounds in the field of pharmaceutical industry, agrochemicals and flavors. The unpredictable results given by new catalysts make the design of effecti
Synthesis and application of new iminopyridine ligands in the enantioselective palladium-catalyzed allylic alkylation
Solinas, Maurizio,Sechi, Barbara,Chelucci, Giorgio,Baldino, Salvatore,Pedro, José R.,Blay, Gonzalo
, p. 73 - 77 (2014/03/21)
A variety of iminopyridines were obtained by condensation of chiral amines with pyridine-2-carboxaldehyde and quinoline-8-carbaldehyde, or of aminoalkylpyridine derivatives with chiral ketones. These ligands were assessed in the enantioselective palladium
Fluorescent OFF-ON polymer chemosensor bonded alternatively with 1,4-dioctyloxybenzene and (R,R)-salen for cascade Zn2+ and chiral recognition
Sakthivel, Sekarpandi,Punniyamurthy, Tharmalingam
experimental part, p. 570 - 576 (2012/08/28)
The synthesis of the chiral main chain polymers 1a-b bonded alternatively with (R,R)-salen and 1,4-dioctyloxybenzene has been described employing a palladium-catalyzed C-C cross-coupling reaction as the key step. They are soluble in common organic solvent
Application of rapidly generated bidentate ligand libraries to zinc catalyzed reductions
Zaman, Tariq,Frauenlob, Robin,McCarthy, Robert,Walsh, Carolyn M.,Bergin, Enda
, p. 159 - 166 (2012/11/13)
A methodology for the combinatorial synthesis of bidentate ligands - allowing direct screening of reaction products without the need for isolation or purification - has been employed in a zinc catalyzed hydrosilylation. This reaction allowed the robustness of the methodology to be examined, by employing it in a challenging case where the metal complex is not pre-formed prior to catalysis. Four different ligand families have been examined: imines, aminals, bis-imines and oxazolines and related compounds, with a small library of each type produced and directly screened in the reaction. Three ligands providing enantioselectivities of 50% or more in this very challenging reaction were identified, and ees and conversions were equivalent whether the ligand was obtained as a crude mixture from a library synthesis or as an isolated, purified compound.
