1604-11-1Relevant articles and documents
BINOL derived monodentate acylphosphite ligands for homogeneously catalyzed enantioselective hydrogenation
Korostylev, Andrei,Monsees, Axel,Fischer, Christine,Boerner, Armin
, p. 1001 - 1005 (2004)
Enantiopure acylphosphites have been prepared based upon chiral nonsubstituted and 3,3′-disubstituted binaphthols in order to elucidate steric and electronic effects on the Rh(I)-catalyzed asymmetric hydrogenation of functionalized olefins. With these new
Chiral Monophosphites and Monophosphonites as Ligands in Asymmetric Transition Metal Catalysis
Reetz
, p. 392 - 396 (2003)
Chiral monophosphites and monophosphonites derived from BINOL are more effective ligands in enantioselective rhodium-catalyzed hydrogenation of olefins, as compared to bidentate bis-phosphites. An appreciable increase in enantioselectivity is attained with the use of mixtures of two different monodentate phosphites and phosphonites in rhodium-catalyzed hydrogentation.
On the economic application of DuPHOS rhodium(I) catalysts: A comparison of COD versus NBD precatalysts
Cobley, Christopher J,Lennon, Ian C,McCague, Raymond,Ramsden, James A,Zanotti-Gerosa, Antonio
, p. 7481 - 7483 (2001)
The effectiveness of cyclooctadiene and norbornadiene precatalysts of the type [Rh(DuPHOS)(diolefin)]BF4 in catalytic asymmetric hydrogenation of various prochiral olefins has been examined. In some of the systems studied, the NBD complex gave
Novel monodentate spiro phosphorus ligands for rhodium-catalyzed hydrogenation reactions
Fu, Yu,Xie, Jian-Hua,Hu, Ai-Guo,Zhou, Hai,Wang, Li-Xin,Zhou, Qi-Lin
, p. 480 - 481 (2002)
Novel monodentate phosphorus ligands containing the 1,1′-spirobiindane backbone have been synthesized and applied in the asymmetric rhodium-catalyzed hydrogenation of functionalized olefins, providing excellent enantioselectivities (up to 99.3% ee).
Rh(I) coordination chemistry of hexacationic Dendriphos ligands and their application in hydroformylation catalysis
Snelders, Dennis J.M.,Kunna, Katharina,Mueller, Christian,Vogt, Dieter,Koten, Gerard Van,Klein Gebbink, Robertus J.M.
, p. 1411 - 1420 (2010)
The coordination chemistry of hexacationic Dendriphos ligands L* with respect to Rh(I), as well as their application in Rh-catalyzed hydroformylation reactions, is described. Complexes of the type RhCl(CO)(L*)2 were synthesized and characterized. The results show that Dendriphos ligands are weaker σ-donors and/or stronger π-acceptors compared to PPh 3. The reaction of L* with [Rh(cod)2]BF4 in MeCN afforded monophosphine-Rh(I) complexes of the type Rh(cod)(MeCN) (L*), which points to the tendency of these ligands to form coordinatively unsaturated metal complexes. The catalytic performance of Dendriphos ligands in the Rh-catalyzed hydroformylation appeared to be dominated by steric effects arising from the large dendritic shells of these ligands. Furthermore, the possibility of tuning the catalytic activity and selectivity of the catalytic species, by changing the six counteranions of the hexacationic Dendriphos ligand, has been investigated. Changing the anions from BF4- to the chiral anions camphorsulphonate or Δ-Trisphat did not render the hydroformylation reaction of styrene enantioselective, albeit small changes in its regioselectivity were observed.
Chiral pyrophosphites - Synthesis and application as ligands in Rh(I)-catalyzed asymmetric hydrogenation
Korostylev, Andrei,Selent, Detlef,Monsees, Axel,Borgmann, Cornelia,Boerner, Armin
, p. 1905 - 1909 (2003)
Enantiopure pyrophosphites have been prepared for the first time based upon two independent synthetic pathways. The new ligands based on binaphthols, which are remarkably stable towards oxidation, were tested in the Rh(I)-catalyzed asymmetric hydrogenation of functionalized olefins, where up to 70% ee could be achieved.
Rhodium-catalyzed enantioselective hydrogenation using chiral monophosphonite ligands
Reetz,Sell
, p. 6333 - 6336 (2000)
Surprisingly high enantioselectivities in the Rh-catalyzed hydrogenation of itaconic acid dimethyl ester and methyl-2-acetamido acrylate are observed upon using chiral monophosphonite ligands derived from binaphthol (ee up to 94%). Although appropriate ch
First enantioselective catalysis using a helical diphosphane
Reetz, Manfred T.,Beuttenmller, Eckart W.,Goddard, Richard
, p. 3211 - 3214 (1997)
The synthesis of 2,15-bis(diphenylphosphino)-hexahelicene (PHelix) in enantiomerically pure form and its use as a helical ligand for enantioselective rhodiumcatalyzed hydrogenation are described.
Synthesis of New Chiral Monodentate Phosphite Ligands and Their Use in Catalytic Asymmetric Hydrogenation
Hua, Zihao,Vassar, Victor C.,Ojima, Iwao
, p. 3831 - 3834 (2003)
(Matrix presented) New monodentate phosphite ligands have been developed from axially chiral biphenols, which show excellent enantioselectivity in the Rh-(I)-catalyzed hydrogenation of dimethyl itaconate. The new chiral ligand system is suitable to create libraries and possesses fine-tuning capability.
α-Phosphanyl amino acids: Diphenylphosphanyl glycines with a chiral N-substituent
Lach, Joanna,Peulecke, Normen,Jones, Peter G.,Dix, Ina,Heinicke, Joachim W.
, p. 795 - 802 (2016)
The first α-phosphanyl amino acetic acids (phosphanyl glycines) with a chiral N-substituent 1a–g have been synthesized by one-pot three-component condensation of diphenylphosphane and enantiomerically pure primary amines of the type (L)- or (R)-R1R2CHNH2with glyoxylic acid monohydrate in diethyl ether at room temperature. Crystals of the N-(1S)-phenylethyl derivative 1d·MeOH, grown from methanol, contained only the (1S,αS)-diastereoisomer. In [d8]THF or CD3OD solution, however, two diastereoisomers were always observed for 1a–g, usually in a diastereoisomeric ratio in the range 67:33% to 80:20%. This, together with the general sensitivity of the phosphanylglycines to hydrolysis, H-D exchange at the acidic α-CH and facile air oxidation in CD3OD solution and decarboxylation on heating in aprotic solvents are serious shortcomings and militate against the use as ligands, e.g. in Rh- or Ir-catalyzed asymmetric hydrogenations. Nickel catalysts, generated in situ with Ni(COD)2in THF and/or 1-hexene, proved however more stable and allowed selective oligomerization of ethylene at 100?°C, probably by formation of a stabilizing [Formula presented])O?hybrid ligand in the catalyst backbone. Complexes and catalysts of this type might thus offer chances for use of this facile available asymmetric ligands.
Repetitive application of a fluorous chiral BINAP-Ru complex in the asymmetric hydrogenation of olefins
Horn, Joachim,Bannwarth, Willi
, p. 2058 - 2063 (2007)
A trisperfluoroalkylsilyl-modified (S)-BINAP ligand has been prepared and its pertinent Ru complex applied to the asymmetric hydrogenation of olefins. Efficient separation of the Ru catalyst by filtration and its reuse was achieved. Relative to the untagg
Polymer-supported monodentate phosphite ligands for asymmetric hydrogenation
Chen, Weiping,Roberts, Stanley M.,Whittall, John
, p. 4263 - 4266 (2006)
Several new polymer-supported monophosphite ligands have been developed and the rhodium complexes were shown to be highly efficient, highly enantioselective and easily separable catalysts for asymmetric hydrogenation of itaconates, enamides, α-dehydroamin
Preparation of enantiomerically pure [3]ferrocenophane-based chelate bis-phosphane ligands and their use in asymmetric alternating carbon monoxide/propene copolymerization
Liptau, Patrick,Tebben, Ludger,Kehr, Gerald,Froehlich, Roland,Erker, Gerhard,Hollmann, Frank,Rieger, Bernhard
, p. 1909 - 1918 (2005)
An intramolecular Mannich reaction (HNMe2, TiCl4) was used to convert 1,1′-diacetylferrocene to the unsaturated amino[3]ferrocenophane 2. Subsequent hydrogenation gave 3. To obtain enantiomerically pure chelate P,P-[3]ferrocenophane ligands the readily available pure dimethylamino[3]ferrocenophane enantiomers (R,R)-3 and (S,S)-3 each were treated with butyllithium followed by chlorodiphenylphosphane to yield the chelate P,N-[3]ferrocenophanes (R,R,Rpl)-10 and (S,S,S pl)-10, respectively. Their treatment with HPPh2 in glacial acetic acid resulted in substitution of the -NMe2 group by -PPh2 with overall retention of configuration to yield (R,R,R pl)-11 and (S,S,Spl)-11, respectively (both characterized by X-ray diffraction). Similarly, the reaction of (R,R,Rpl)-10 or (S,S,Spl)-10 with dicyclohexylphosphane/HOAc yielded the pure (R,R,Rpl)-12 and (S,S,Spl)-12 enantiomers, respectively. Both these compounds were also characterized by X-ray crystal structure analyses. (R,R,Rpl)-12 was employed in catalytic asymmetric hydrogenation and also in asymmetric alternating carbon monoxide/propene copolymerization. A catalyst that was generated in situ from the chelate P,P-[3]ferrocenophane ligand and palladium acetate gave the CO/propene alternating copolymer with a good activity and high asymmetric induction. The catalyst derived from the reaction of (R,R,Rpl)-11 with [Rh(cod) 2]BF4 was employed in the enantioselective hydrogenation of dimethyl itaconate (DMI) (13, ca. 95% ee, R-configured product) and methyl α-acetamidocinnamate (MAC) 14 (ca. 24% ee, R-configured product). Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Homogeneous Asymmetric Hydrogenation Using a Chiral Phosphinite Derivative of Carbohydrates as Ligand
Yamashita, Mitsuji,Kobayashi, Mineaki,Sugiura, Motoyuki,Tsunekawa, Kenji,Oshikawa, Tatsuo,et al.
, p. 175 - 178 (1986)
Diphenylphosphinite derivatives of sugars were conveniently synthesized by the reaction of diphenylphosphinous chloride-triethylamine with sugar derivatives.Homogeneous asymmetric hydrogenations of several prochiral olefins, i.e., (Z)-α-acetylaminocinnamic acid, (Z)-α-benzoylaminocinnamic acid, itaconic acid, tiglic acid, and their esters, were carried out using rhodium(I) catalysts with the tervalent chiral phosphorus derivative of sugars.The highest optical yields for all the prochiral substrates investigated were obtained when di-μ-chloro-bis(cyclooctadiene)dirhodium(I) and methyl 2,3-O-isopropylidene-4-O-(diphenylphosphino)-α-L-rhamnopyranoside were used.
The inhibiting influence of aromatic solvents on the activity of asymmetric hydrogenations
Heller, Detlef,Drexler, Hans-Joachim,Spannenberg, Anke,Heller, Barbara,You, Jingsong,Baumann, Wolfgang
, p. 777 - 780 (2002)
Blocking the catalyst through the formation of RhI-η6-arene complexes (the complex [Rh((R,R)-Et-DuPHOS)(C6H6)]+ is shown; Et-DuPHOS = 2′,5′,2″,5″-tetraethyl-1,2-bis(phospholanyl)benzene) can decrease the activity of asymmetric hydrogenations. The inhibiting effects of aromatic compounds were quantified by means of kinetic measurements and confirmed by means of X-ray crystal structure analysis and 103Rh NMR spectroscopy.
New bidentate phosphorus ligands based on a norbornane backbone for rhodium-catalyzed asymmetric hydrogenation
Cai, Chonglin,Deng, Fanguo,Sun, Wei,Xia, Chungu
, p. 3007 - 3010 (2007)
A new class of bidentate diphosphite and diphosphinite ligands has been developed from inexpensive norbornadiene. These ligands exhibited excellent enantioselectivities in the Rh(I)-catalyzed asymmetric hydrogenation of olefin derivatives (up to 99.9% ee)
Construction and probing of multisite chiral catalysts: Dendrimer fixation of C2-symmetrical diphosphinerhodium complexes
Engel, Gerald D.,Gade, Lutz H.
, p. 4319 - 4329 (2002)
A series of chiral phosphine-functionalized poly(propyleneimine) (PPI) dendrimers was synthesized by the reaction of carboxyl-linked C2-chiral pyrphos ligand (pyrphos=3,4-bis(diphenylphosphino)pyrrolidine) with zeroth-fourth generation PPI using ethyl-N,N-dimethylaminopropylcarbodiimide (EDC)/1-hydroxybenzotriazol as a coupling reagent. The dendrimers obtained were characterized by NMR spectroscopy and elemental analysis as well as FAB and MALDI-TOF mass spectrometry, which established their molecular masses of up to 20 700 amu. Metalation of the multi-site phosphines with [Rh(COD)2]- BF4 cleanly yielded the cationic rhododendrimers containing up to 32 metal centers (for the fourth generation species), representing the largest chiral phosphine dendrimer catalyst studied to date. The complete metalation of the chiral phosphine sites was demonstrated by 31P NMR spectroscopy and the observation of the coordination-shifted AB part of the ABX spin system (δA = 33.9, δB = 32.9; 1JRh.P = 150, 153 Hz; 2JP.P = 28 Hz). The relationship between the size/generation of the dendrimer and its catalytic properties was established in the asymmetric hydrogenation of Z- methyl-α-acetamidocinammate and dimethyl itaconate. A decrease in both activity and selectivity of the dendrimer catalysts was observed on going to the higher generations.
Rhodium-catalyzed asymmetric hydrogenations of electron deficient olefins using 1,4-diphosphine ligands bearing an imidazolidin-2-one backbone
Lee, Sang-gi,Zhang, Yong Jian
, p. 1039 - 1042 (2002)
In rhodium(I)-catalyzed asymmetric hydrogenations of electron deficient olefins, the electron-rich and sterically encumbered phosphine ligand, MOD-BDPMI, exhibited higher enantioselectivities than BDPMI ligands. Moreover, the N-substituents of the imidazolidin-2-one backbone affected the enantioselectivity. Thus, using the N,N′-dimethylated MOD-BDPMI ligand 2b, (Z)-α-(N-acetamido)cinnamic acid 3 was hydrogenated with 100% conversion to give the saturated α-amino acid with ee of 88.7%.
Enantioselective hydrogenation with inexpensive, easily available monodentate phosphite ligands
Chen, Weiping,Xiao, Jianliang
, p. 2897 - 2899 (2001)
Diastereomerically pure menthyl binaphthylphosphite ligands, easily accessible from the inexpensive, racemic binaphthol, l-menthol and PCl3, are shown to be effective in the rhodium-catalysed enantioselective hydrogenation of prochiral olefins.
Borohydride reduction of acetophenone and esters of dehydrocarboxylic acids in the presence of chiral cobalt(II) diamine complexes
Nindakova,Shainyan
, p. 348 - 353 (2005)
The catalytic reduction of acetophenone, methyl α-acetamidocinnamate, and dimethyl itaconate with alcohol-modified sodium borohydride was studied in the presence of complexes CoCl2·L2 (L2 are chiral C 2-symmetric diamines: (4S,5S)-2,2-dimethyl-4,5- bis(aminomethyl)-1,3-dioxolane, (4S, 5S)-2,2-dimethyl-4,5-bis(methylaminomethyl) -1,3-dioxolane, (4S, 5S)-2,2-dimethyl-4,5-bis(dimethylaminomethyl)-1,3- dioxolane, and (4S, 5S)-2,2-dimethyl-4,5-bis(diphenylaminomethyl)-1,3-dioxolane) . The maximum enantiomeric excess of (S)-1-phenylethanol was 24%, that of dimethyl α-methylsuccinate was 38%.
Directed orthogonal self-assembly of homochiral coordination polymers for heterogeneous enantioselective hydrogenation
Yu, Liting,Wang, Zheng,Wu, Jiang,Tu, Shujiang,Ding, Kuiling
, p. 3627 - 3630 (2010)
Three in one: Orthogonal coordination of FeII and RhI with a single heteroditopic ligand results in the formation of selfsupported heterogeneous chiral catalysts (see scheme). The compounds are highly active, enantioselective, and re
New modular P-chiral ligands for Rh-catalyzed asymmetric hydrogenation
Bondarev, Oleg G.,Goddard, Richard
, p. 9013 - 9015 (2006)
New modular P-chiral ligands have been prepared from commercially available (S)-α,α-diphenylprolinol. With these new types of ligands, up to 95% ee was achieved in the Rh-catalyzed asymmetric hydrogenation of functionalized olefins.
Continuous asymmetric hydrogenation in supercritical carbon dioxide using an immobilised homogeneous catalyst
Stephenson, Phil,Kondor, Betti,Licence, Peter,Scovell, Katherine,Ross, Stephen K.,Poliakoff, Martyn
, p. 1605 - 1610 (2006)
Continuous flow supercritical carbon dioxide (scCO2) has previously been shown (P. Stephenson, P. Licence, S. K. Ross, M. Poliakoff, Green Chem. 2004, 6, 521) to be a viable medium for conducting continuous asymmetric hydrogenation when it is combined with an appropriate enantioselective catalyst. Here we examine the use of a composite catalyst immobilisation system modified with several different types of asymmetric bisphosphine ligands in continuous flow ScCO2. In particular, proprietary ligands from Solvias AG were found to be the most successful, with Josiphos 001 improving the enantiomeric excess (ee) to > 80 % in the asymmetric hydrogenation of dimethyl itaconate (DMIT); this ee is higher than that reported for the batch hydrogenation of DMIT using a homogeneous catalyst fully dissolved in scCO2 (S. Lange, A. Brinkmann, P. Trautner, K. Woelk, J. Bargon, W. Leitner, Chirality 2000, 12, 450).
A single enantiomer (99 %) directly from continuous-flow asymmetric hydrogenation
Duque, Ruben,Pogorzelec, Peter J.,Cole-Hamilton, David J.
, p. 9805 - 9807 (2013)
Chemistry in a shower: Dibutyl itaconate is hydrogenated in a solventless reaction to dibutyl (S)-(-)-methylsuccinate at ambient temperature and 5 bar. The product is recovered directly from a flow system. Copyright
Correlation between the Selectivity and the Structure of an Asymmetric Catalyst Built on a Chirally Amplified Supramolecular Helical Scaffold
Desmarchelier, Alaric,Caumes, Xavier,Raynal, Matthieu,Vidal-Ferran, Anton,Van Leeuwen, Piet W. N. M.,Bouteiller, Laurent
, p. 4908 - 4916 (2016)
For the first time, supramolecular helical rods composed of an achiral metal complex and a complementary enantiopure monomer provided a good level of enantioinduction in asymmetric catalysis. Mixtures containing an achiral ligand monomer (BTAPPh2, 2 mol %) and an enantiopure ligand-free comonomer (ester BTA, 2.5 mol %), both possessing a complementary benzene-1,3,5-tricarboxamide (BTA) central unit, were investigated in combination with [Rh(cod)2]BArF (1 mol %) in the asymmetric hydrogenation of dimethyl itaconate. Notably, efficient chirality transfer occurs within the hydrogen-bonded coassemblies formed by BTA Ile and the intrinsically achiral catalytic rhodium catalyst, providing the hydrogenation product with up to 85% ee. The effect of the relative content of BTA Ile as compared to the ligand was investigated. The amount of chiral comonomer can be decreased down to one-fourth of that of the ligand without deteriorating the enantioselectivity of the reaction, while the enantioselectivity decreases for mixtures containing high amounts of BTA Ile. The nonlinear relationship between the amount of chiral comonomer and the enantioselectivity indicates that chirality amplification effects are at work in this catalytic system. Also, right-handed helical rods are formed upon co-assembly of the achiral rhodium complex of BTAPPh2 and the enantiopure comonomer BTA Ile as confirmed by various spectroscopic and scattering techniques. Remarkably, the major enantiomer and the selectivity of the catalytic reaction are related to the handedness and the net helicity of the coassemblies, respectively. Further development of this class of catalysts built on chirally amplified helical scaffolds should contribute to the design of asymmetric catalysts operating with low amounts of chiral entities.
Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources
Doyle, Abigail G.,Gandhi, Shivaani S.,Jiang, Shutian,Kariofillis, Stavros K.,Martinez Alvarado, Jesus I.,?urański, Andrzej M.
supporting information, p. 1045 - 1055 (2022/01/19)
Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.
PHANE-TetraPHOS, the First D2 Symmetric Chiral Tetraphosphane. Synthesis, Metal Complexation, and Application in Homogeneous Stereoselective Hydrogenation
Benincori, Tiziana,Cirilli, Roberto,Pierini, Marco,Rizzo, Simona,Terraneo, Giancarlo,Vaghi, Luca
, p. 2367 - 2374 (2021/06/25)
PHANE-TetraPHOS, a new D2 symmetric tetraphosphane based on the [2.2]paracyclophane scaffold, has been synthesized and characterized. The peculiarity of this system is the presence of four homotopic diphenylphosphane groups, exchangeable through C2 symmetry operations and consequently indistinguishable. Their spatial arrangement allows the simultaneous complexation of two metal atoms. Enantiomeric purity was attained at tetra-phosphane oxide level by fractional crystallization of the diastereomeric adducts obtained from the racemate with enantiopure dibenzoyltartaric acids. Alkaline treatment of diastereomerically pure adducts followed by exhaustive P?O groups reduction with HSiCl3 gave both PHANE-TetraPHOS antipodes in an enantiopure state. They were tested as rhodium ligands in the homogeneous enantioselective hydrogenation of some benchmark unsaturated compounds. Catalytic activity and enantiodiscrimination ability were found comparable to those exhibited by the complexes of the parent bidentate ligand PHANEPHOS, but only half a mole of precious chiral ligand was employed.
Generation of Functionalized Alkyl Radicals via the Direct Photoexcitation of 2,2′-(Pyridine-2,6-diyl)diphenol-Based Borates
Miyamoto, Yusuke,Sumida, Yuto,Ohmiya, Hirohisa
supporting information, p. 5865 - 5870 (2021/07/31)
A new type of alkylborate was developed for the purpose of generating radicals via direct photoexcitation. These borates were prepared using 2,2′-(pyridine-2,6-diyl)diphenol as a tridentate ligand together with organoboronic acids or potassium trifluoroborates. The ready availability of organoboron compounds is a significant advantage of this direct photoexcitation protocol. The excited states of these borates can also serve as strong reductants, enabling various transformations.
