- Cobalt-Catalyzed Allylic Alkylation Enabled by Organophotoredox Catalysis
-
Co-catalyzed allylic substitution reactions have received little attention, arguably because of the lack of any known advantage of Co catalysis over either Rh or Ir catalysis. Described here is a general and regioselective Co-catalyzed allylic alkylation using an in situ catalyst activation by organophotoredox catalysis. This noble-metal-free catalytic system exhibits unprecedentedly high reactivities and regioselectivities for the allylation with an allyl sulfone, for the first time, representing the unique synthetic utility of the Co-catalyzed method compared to the related Rh- and Ir-catalyzed reactions.
- Takizawa, Koji,Sekino, Tomoyuki,Sato, Shunta,Yoshino, Tatsuhiko,Kojima, Masahiro,Matsunaga, Shigeki
-
p. 9199 - 9203
(2019/06/04)
-
- Enantioselective Ir-Catalyzed Allylic Alkylation of Racemic Allylic Alcohols with Malonates
-
Ir-catalyzed enantioselective allylic alkylation of branched racemic allylic alcohols with malonates is described. Enabled by Carreira's chiral Ir/(P, olefin) complex, the method described allows allylic substitution with various aromatic alcohols and mal
- Meng, Chun-Yan,Liang, Xiao,Wei, Kun,Yang, Yu-Rong
-
supporting information
p. 840 - 843
(2019/01/30)
-
- An improved class of phosphite-oxazoline ligands for Pd-catalyzed allylic substitution reactions
-
A method for generation of Pd/phosphite-oxazoline catalysts containing an alkyl backbone chain has been successfully applied to Pd-catalyzed allylic substitution reactions. By carefully selecting the substituents at both the alkyl backbone chain and the oxazoline of the ligand, as well as the configuration of the biaryl phosphite group, high activities (TOF > 8000 mol substrate × (mol Pd × h)?1) and excellent enantioselectivities (ee's up to 99%) have been achieved for many hindered and unhindered substrates with a wide range of C-, O-, and N-nucleophiles (73 substitution products in total). Moreover, DFT and NMR studies of the key Pd-allyl complexes allowed us to better understand the origin of the excellent enantioselectivities observed experimentally. The useful application of the Pd/phosphite-oxazoline catalysts was demonstrated by the syntheses of many chiral carbobicycles, with multiples stereocenters, by simple sequential reactions involving Pd-allylic substitution and either 1,6-enyne cyclization or Pauson?Khand enyne cyclization.
- Biosca, Maria,Salto, Joan,Magre, Marc,Norrby, Per-Ola,Pamies, Oscar,Dieguez, Montserrat
-
p. 6033 - 6048
(2019/07/19)
-
- Regio- and Enantioselective Rhodium-Catalyzed Allylic Alkylation of Racemic Allylic Alcohols with 1,3-Diketones
-
Highly regio- and enantioselective rhodium-catalyzed allylic alkylation of 1,3-diketones with racemic secondary allylic alcohols is reported. In the presence of a Rh-catalyst derived from the Carreira (P, olefin)-ligand and TFA as an additive, chiral branched α-allylated 1,3-diketones could be obtained in good to excellent yields, with excellent regio- and enantioselectivity (b/l > 19/1, 86-98% ee). The direct utilization of allyl alcohols as electrophiles represents an improvement from the viewpoint of an atom economy. Both aryl- and aliphatic-substituted allyl alcohols are suitable substrates with excellent reaction outcomes. This reaction features mild conditions, broad substrate scope, and readily available substrates.
- Tang, Sheng-Biao,Zhang, Xiao,Tu, Hang-Fei,You, Shu-Li
-
supporting information
p. 7737 - 7742
(2018/06/04)
-
- Iridium/ N-Heterocyclic Carbene Complex-Catalyzed Intermolecular Allylic Alkylation Reaction
-
N-Heterocyclic carbenes (NHCs) were found to be suitable ligands in Ir-catalyzed intermolecular allylic alkylation reaction. In the presence of a catalyst derived from [Ir(dncot)Cl]2 (dncot = dinaphthocyclooctatetraene) and triazolium salt L7,
- Bao, Can-Can,Zheng, Dong-Song,Zhang, Xiao,You, Shu-Li
-
p. 4763 - 4772
(2019/01/04)
-
- Efficient stereochemical communication in phosphine-amine palladium-complexes: Exploration of N-substituent effects in coordination chemistry and catalysis
-
Six-membered chelate complexes of type [Pd(1a-e)Cl2] (2a-e) and [Pd(1a-e)(η3-PhCHCHCHPh)]BF4 (3a-e) of a series of systematically varied chiral phosphine-amine ligands (S,S)-Ph2PCH(CH3)CH2C
- Farkas, Gergely,Császár, Zsófia,Stágel, Kristóf,Nemes, Evelin,Balogh, Szabolcs,Tóth, Imre,Bényei, Attila,Lendvay, Gy?rgy,Bakos, József
-
p. 129 - 140
(2017/06/19)
-
- Palladium-Based Supramolecularly Regulated Catalysts for Asymmetric Allylic Substitutions
-
Herein is reported the effect of different polyether binders (alkali metal, alkaline earth metal, and lanthanide salts) as regulation agents to enhance the catalytic properties of palladium complexes derived from enantiopure bisphosphite ligands in allyli
- Rovira, Laura,Fernández-Pérez, Héctor,Vidal-Ferran, Anton
-
p. 528 - 533
(2016/03/01)
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- Conformational Preferences of a Tropos Biphenyl Phosphinooxazoline-a Ligand with Wide Substrate Scope
-
Excellent enantioselectivities are observed in palladium-catalyzed allylic substitutions of a wide range of substrate types and nucleophiles using a bidentate ligand composed of oxazoline and chirally flexible biaryl phosphite elements. This unusually wid
- Bellini, Rosalba,Magre, Marc,Biosca, Maria,Norrby, Per-Ola,Pàmies, Oscar,Diéguez, Montserrat,Moberg, Christina
-
p. 1701 - 1712
(2016/03/15)
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- Diphosphorus Ligands Containing a P-Stereogenic Phosphane and a Chiral Phosphite or Phosphorodiamidite – Evaluation in Pd-Catalysed Asymmetric Allylic Substitution Reactions
-
The synthesis of 14 new optically pure C1-symmetric phosphane–phosphinite (1–4), phosphane–phosphite (5–9) and phosphane–phosphorodiamidite (10–14) ligands is reported. The ligands were prepared through the condensation of (2-hydroxyphenyl)phenylphosphanes PPh(2-PhOH)R (R = Me, tBu and Ph) with chlorodiisopropylphosphane (1 and 2), chlorodiphenylphosphane (3 and 4), the chlorodioxaphosphepine derived from both enantiomers of 1,1′-bi-2-naphthol (5–9) and the chlorodiazaphosphepine derived from both enantiomers of N,N′-dimethyl-1,1′-binaphthyl-2,2′-diamine (10–14) in the presence of a base. With these ligands, cationic Pd complexes of the type [Pd(η3-C4H7)(PP′)]PF6(Pd1–Pd14) were obtained and characterised; the crystal structures of Pd1, Pd2 and Pd13 were obtained. In solution, the complexes are present as mixtures of two diastereomers because of the lack of symmetry of the ligand and the presence of the methallyl group. The Pd complexes catalyse the allylic alkylation with dimethyl malonate and the amination with benzylamine of the model substrate rac-3-acetoxy-1,3-diphenyl-1-propene (I). For the alkylation, full conversions and good enantioselectivities (up to 96 % ee with Pd14) were observed.
- Clavero, Pau,Grabulosa, Arnald,Rocamora, Mercè,Muller, Guillermo,Font-Bardia, Mercè
-
supporting information
p. 4054 - 4065
(2016/09/13)
-
- Palladium-catalyzed enantioselective allylic substitution in the presence of monodentate furanoside phosphoramidites
-
A library of monodentate furanoside phosphoramidites, easily synthesized from inexpensive D-xylose and optically pure 1,1-bi-2-naphthol (BINOL), was used as ligands for the palladium-catalyzed allylic alkylation and amination. The matched pair was formed from D-xylose-derivatives and (S)-BINOL. The asymmetric induction depends strongly on the substituent at the C5 of the carbohydrate backbone; both bulky 5-O-pivaloyl and 5-deoxy derivatives gave excellent results, whereas ligands with trityl protection at position C5 induced low ee values with reversal of configuration. The solvent used for the addition is also of great importance with highest enantioselectivities observed in diethyl ether. The best results for both alkylation and amination, up to 98-99 ee, were obtained for sterically demanding allylic acetates. Single is better: New carbohydrate ligands bearing a single 1,1-bi-2-naphthol (BINOL)-derived phosphoramidite moiety are developed and successfully applied to the palladium-catalyzed asymmetric allylic substitution. The enantioselectivities are equal or better than those obtained for similar systems containing two BINOL moieties and reach up to 99 ee.
- Majdecki, Maciej,Jurczak, Janusz,Bauer, Tomasz
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p. 799 - 807
(2015/03/14)
-
- Origins of Regioselectivity in Iridium Catalyzed Allylic Substitution
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Detailed studies on the origin of the regioselectivity for formation of branched products over linear products have been conducted with complexes containing the achiral triphenylphosphite ligand. The combination of iridium and P(OPh)3 was the first catalytic system shown to give high regioselectivity for the branched product with iridium and among the most selective for forming branched products among any combination of metal and ligand. We have shown the active catalyst to be generated from [Ir(COD)Cl]2 and P(OPh)3 by cyclometalation of the phenyl group on the ligand and have shown such species to be the resting state of the catalyst. A series of allyliridium complexes ligated by the resulting P,C ligand have been generated and shown to be competent intermediates in the catalytic system. We have assessed the potential impact of charge, metal-iridium bond length, and stability of terminal vs internal alkenes generated by attack at the branched and terminal positions of the allyl ligand, respectively. These factors do not distinguish the regioselectivity for attack on allyliridium complexes from that for attack on allylpalladium complexes. Instead, detailed computational studies suggest that a series of weak, attractive, noncovalent interactions, including interactions of H-bond acceptors with a vinyl C - H bond of the alkene ligand, favor formation of the branched product with the iridium catalyst. This conclusion underscores the importance of considering attractive interactions, as well as repulsive steric interactions, when seeking to rationalize selectivities.
- Madrahimov, Sherzod T.,Li, Qian,Sharma, Ankit,Hartwig, John F.
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p. 14968 - 14981
(2015/12/08)
-
- Synthesis of 1-[bis(trifluoromethyl)phosphine]-1'- oxazolinylferrocene ligands and their application in regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates
-
A class of novel, easily accessible and air-stable 1-[bis(trifluoromethyl) phosphine]-1'-oxazolinylferrocene ligands has been synthesized from ferrocene. It became apparent that these ligands can be used in the regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates in a highly efficient manner. Excellent regio- and enantioselectivity could be obtained for a wide range of substrates.
- Lai, Zeng-Wei,Yang, Rong-Fei,Ye, Ke-Yin,Sun, Hongbin,You, Shu-Li
-
supporting information
p. 1261 - 1266
(2014/06/24)
-
- Highly enantioselective alkylation of allyl acetates using tartrate-derived bioxazoline ligands
-
Tartrate-derived bioxazoline ligands, which form a five-membered chelate ring with metals, were evaluated for use in the asymmetric allylic alkylation (AAA) reactions of various symmetrical and unsymmetrical allyl acetates. Excellent enantioselectivities
- Jayakumar, Samydurai,Prakash, Muthuraj,Balaraman, Kaluvu,Kesavan, Venkitasamy
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p. 606 - 615
(2014/02/14)
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- Highly Enantioselective Alkylation of Allyl Acetates Using Tartrate-Derived Bioxazoline Ligands
-
Tartrate-derived bioxazoline ligands, which form a five-membered chelate ring with metals, were evaluated for use in the asymmetric allylic alkylation (AAA) reactions of various symmetrical and unsymmetrical allyl acetates. Excellent enantioselectivities were achieved by using both symmetrical and unsymmetrical allyl acetates. Palladium(II)-catalyzed asymmetric allylic alkylation reactions of various symmetrical and unsymmetrical allyl acetates were achieved by using bioxazoline ligands, which were derived from tartaric acid, to give products with excellent enantioselectivity.
- Jayakumar, Samydurai,Prakash, Muthuraj,Balaraman, Kaluvu,Kesavan, Venkitasamy
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p. 606 - 615
(2015/10/05)
-
- Kinetico-mechanistic insights on the assembling dynamics of allyl-cornered metallacycles: The Pt-Npy bond is the keystone
-
The square-like homo- and heterometallamacrocycles [{Pd(η3-2-Me-C3H4)(Ln)2}2{M(dppp)}2](CF3SO3)6 (dppp = 1,3-bis(diphenylphosphino)propane) and [
- Angurell, Inmaculada,Ferrer, Montserrat,Gutrrez, Albert,Martnez, Manuel,Rocamora, Merc,Rodguez, Laura,Rossell, Oriol,Lorenz, Yvonne,Engeser, Marianne
-
p. 14473 - 14487
(2015/04/16)
-
- Ruthenium-catalyzed regioselective allylic trifluoromethylthiolation reaction
-
An efficient Ru-catalyzed regioselective allylic trifluoromethylthiolation reaction of allylic carbonates was developed. The linear allylic trifluoromethyl thioethers were obtained in 52-91% yields. Mechanistic investigation revealed that this reaction proceeds via a double allylic trifluoromethylthiolation sequence.
- Ye, Ke-Yin,Zhang, Xiao,Dai, Li-Xin,You, Shu-Li
-
p. 12106 - 12110
(2015/01/09)
-
- A bis(triazolecarboxamido) ligand for enantio- and regioselective molybdenum-catalyzed asymmetric allylic alkylation reactions
-
A modular, enantiomerically pure bis(1H-1,2,3-triazole-4-carboxamide) has been assembled from N,N'-[(1R,2R)-cyclohexane-1,2-diyl]dipropiolamide through a copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction and evaluated as a ligand in the molybde
- Ozkal, Erhan,Pericas, Miquel A.
-
supporting information
p. 711 - 717
(2014/04/03)
-
- Nickel(II) and Palladium(II) complexes of the small-bite-angle p-stereogenic diphosphine ligand MaxPHOS and Its monosulfide
-
Coordination studies of the optically pure diphosphine ligand (t-Bu) 2P(NH)P(t-BuMe) (MaxPHOS) and its monosulfide with several Pd and Ni moieties are described. Treatment of a solution of MaxPHOS·HBF 4 with [M(acac)2] (M
- Grabulosa, Arnald,Doran, Sean,Brandariz, Guillem,Muller, Guillermo,Benet-Buchholz, Jordi,Riera, Antoni,Verdaguer, Xavier
-
p. 692 - 701
(2014/03/21)
-
- Expanding the scope of the elpaN-type library: Glucose-derived bis(pyridine-2-carboxamide) ligands (elpaN-Py) for molybdenum-catalyzed asymmetric allylic alkylations
-
The elpaN-Py family of ligands, which represents a subset of the elpaN-type library based on d-glucose, is described. The ligands are structural analogs of the privileged bis(pyridine-2-carboxamides) derived from trans-1,2- diaminocyclohexane, and differ
- Lega, Matteo,Figliolia, Rosario,Moberg, Christina,Ruffo, Francesco
-
p. 4061 - 4065
(2013/06/26)
-
- Enantioselective synthesis of angularly substituted 1-azabicylic rings: Coupled dynamic kinetic epimerization and chirality transfer
-
A new strategy for enantioselective synthesis of azacyclic molecules in which dynamic kinetic equilibration of diastereomeric iminium ions precedes a stereochemistry-determining sigmatropic rearrangement is reported. The method is illustrated by the synthesis, in high enantiomeric purity (generally 95-99% ee), of a variety of 1-azabicyclic molecules containing angular allyl or 3-substituted 2-propenyl side chains adjacent to nitrogen and up to three stereogenic centers. In these products, the size of the carbocyclic ring is varied widely (5-12 membered); however, useful yields are obtained in forming 1-azabicyclic products containing only fused pyrrolidine and piperidine rings. Chirality transfer from substituents at carbons 1 and 2 of the 3-butenylamine fragment of the starting material is investigated, with methyl and phenyl substituents at the allylic position shown to provide exquisite stereocontrol (generally 98-99% chirality transfer). An attractive feature of the method is the ability to carry out the key transformation in the absence of solvent. Illustrated also is the high yielding conversion of four such products to a new family of bicyclic β-amino acids of high enantiomeric purity.
- Aron, Zachary D.,Ito, Tatsuya,May, Tricia L.,Overman, Larry E.,Wang, Jocelyn
-
p. 9929 - 9948
(2013/10/22)
-
- Bis(perfluoroalkyl) phosphino-oxazoline: A modular, stable, strongly π-accepting ligand for asymmetric catalysis
-
A new class of stable, strongly π-accepting and modular bis-(perfluoroalkyl)-phosphine-oxazoline ligands (FOX) as CO mimics was prepared. It was demonstrated that these ligands, when coordinated to palladium catalysts, promote the asymmetric alkylation of monosubstituted allyl substrates with excellent regio- and enantioselectivity. Solid and solution structure analysis of the FOX-ligated Pd-allyl intermediate reveals that the combination of relative steric and strong trans influences presented by the P(CF 3)2 moiety gave rise to the excellent selectivity.
- Hu, Zongjian,Li, Yuguang,Liu, Kai,Shen, Qilong
-
p. 7957 - 7967
(2013/01/15)
-
- Iridium-catalyzed allylic alkylation reaction with N-aryl phosphoramidite ligands: Scope and mechanistic studies
-
A series of N-aryl phosphoramidite ligands has been synthesized and applied to iridium-catalyzed allylic alkylation reactions, offering high regio- and enantioselectivities for a wide variety of substrates. These ligands feature the synthetic convenience and good tolerance of the ortho-substituted cinnamyl carbonates. Mechanistic studies, including DFT calculations and X-ray crystallographic analyses of the (π-allyl)-Ir complexes, reveal that the active iridacycle is formed via C(sp2)-H bond activation.
- Liu, Wen-Bo,Zheng, Chao,Zhuo, Chun-Xiang,Dai, Li-Xin,You, Shu-Li
-
supporting information; experimental part
p. 4812 - 4821
(2012/04/23)
-
- C1-Symmetric carbohydrate diphosphite ligands for asymmetric Pd-allylic alkylation reactions. Study of the key Pd-allyl intermediates
-
A series of C1-symmetrical 1,3-diphosphite ligands with a furanoside backbone have been applied in the Pd-catalysed asymmetric allylic alkylation of mono- and disubstituted linear substrates. These diphosphite ligands were designed by selective
- Gual, Aitor,Castillon, Sergio,Pamies, Oscar,Dieguez, Montserrat,Claver, Carmen
-
experimental part
p. 2852 - 2860
(2011/05/14)
-
- Better performance of monodentate P-stereogenic phosphanes compared to bidentate analogues in Pd-catalyzed asymmetric allylic alkylations
-
The cationic allylpalladium complexes 3a-3f, 4a, 4e, 5e of type [Pd(η3-2-Me-C3H4)P2]PF 6 were synthesized using a group of monodentate P-stereogenic phosphanes, P=PPhRR' (a-f) and diphosphanes (PhRPCH2)2 (1a, 1e) or PhRPCH2Si(Me)2CH2PPhR (2e). The analogous cationic complexes with the disubstituted allyl group (η3-1,3-Ph2-C3H3) and monodentate phosphanes were not isolated as stable solids: only [PdCl(η3-1,3-Ph2-C3H3)P] (6a, 6d) were obtained. Palladium allyl complexes were screened as precatalysts in the allylic substitution of rac-3-acetoxy-1,3-diphenyl-1-propene (I) and (E)-3-acetoxy-1-phenyl-1-propene (III) with dimethyl malonate as the nucleophile. The various catalytic precursors showed a wide range of activity and selectivity. The bismonodentate phosphane complexes 3 are more active than the bidentate analogues. With regard to the regioselectivity, precursors containing monodentate phosphanes favour the formation of the linear product in the allylic substitution of cinnamyl acetate (III) compared with those containing bidentate phosphanes. With substrate I, compounds with the diphosphanes 1a and 1e, containing a five-membered chelate ring, gave low enantioselectivities (less than 10% ee), but those with the diphosphane 2e, forming a six-membered chelate ring or with two monodentate phosphanes, afforded products with moderate enantioselectivity under standard conditions (ee up to 74 %). The results show that the performance of precursors containing monodentate phosphanes was superior to those containing bidentate ligands in both activity and selectivity.
- Grabulosa, Arnald,Muller, Guillermo,Ceder, Rosa,Maestro, Miguel Angel
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scheme or table
p. 3372 - 3383
(2011/01/07)
-
- Norbornene bidentate ligands: coordination chemistry and enantioselective catalytic applications
-
N- and P-donor derivatives have been prepared by functionalization of a readily available norbomene precursor. Palladium, catalytic systems containing these new ligands were applied in allylic substitution, and yielded high, activities and excellent enantioselectivities for the allylic alkylation and amination reactions (ee up to 97%). A full coordination analysis of the catalytic precursors including modelling studies was also carried, out.
- Fernandez, Fernando,Gual, Aitor,Claver, Carmen,Castillon, Sergio,Muller, Guillermo,Gomez, Montserrat
-
experimental part
p. 758 - 766
(2010/06/12)
-
- Platinum(II) chloride-catalyzed stereoselective domino enyne isomerization/diels-alder reaction
-
Chiral 1,6-enynes were prepared via Ir-catalyzed allylic substitutions. Their platinum(II) chloride-catalyzed domino enyne isomerization/Diels-Alder reaction provided stereoselective access to complex heterocycles. Very high diastereoselectivity was induc
- Schelwies, Mathias,Farwick, Andreas,Rominger, Frank,Helmchen, Guenter
-
scheme or table
p. 7917 - 7919
(2011/02/25)
-
- Modular chiral diphosphite derived from l-tartaric acid. Applications in metal-catalyzed asymmetric reactions
-
A new family of C2-symmetric chiral diphosphites was synthesized using two different chiral backbones derived from tartaric acid, combined with chiral binaphthyls or non-chiral substituted biphenyl moieties. Diphosphites were applied to Rh-catalyzed hydroformylation of styrene producing good conversions in mild conditions, fair regioselectivities but low enantioselectivities in all cases. Ligands were also essayed in Pd-catalyzed allylic substitution reactions of linear and cyclic substrates using dimethyl malonate as nucleophile. Conversion rates up to 7200 h-1 were reached, while moderated ee's were attained. In this reaction, a kinetic resolution of rac-1,3-diphenyl-3-acetoxyprop-1-ene was observed, leading to 99% ee of for the unreacted S-substrate and 60% ee of S-alkylated product. Coordination properties of diphosphites in rhodium and palladium complexes related to catalytic species involved in the two previous reactions were investigated. Some ligands form equatorial-equatorial chelates in pentacoordinated complexes [RhH(CO)(PPh3)(diphosphite)], while other act as bridge between two metal atoms. In the catalytic active species [Pd(η3-PhCHCHCHPh)(diphosphite)]PF6 one or two diastereoisomers are formed, depending on the diphosphite structure.
- Rosas-Hernández, Alonso,Vargas-Malvaez, Edgar,Martin, Erika,Crespi, Laura,Bayón, J. Carles
-
experimental part
p. 68 - 75
(2010/11/05)
-
- New 1,2,4,5-tetrakis-(N-imidazoliniummethyl)benzene and 1,2,4,5-tetrakis-(N-benzimidazoliummethyl)benzene salts as N-heterocyclic tetracarbene precursors: synthesis and involvement in ruthenium-catalyzed allylation reactions
-
New tetraimidazolinium and tetrabenzimidazolium salts have been prepared. Upon reaction with tBuOK, they generate carbene ligands, which were associated in situ to [RuCp*(MeCN)3]PF6 to produce new ruthenium catalysts that
- Gürbüz, Nevin,Demir, Serpil,?zdemir, Ismail,Cetinkaya, Bekir,Bruneau, Christian
-
experimental part
p. 1346 - 1351
(2010/04/02)
-
- Enantiomerically Pure P,N Chelates Based on Phospholene Rings: Palladium Complexes and Catalytic Applications in Allylic Substitution
-
The synthesis of optically pure 2-pyridylphospholene ligands by diastereomeric resolution of PdII complexes, bearing the corresponding racemic P,N ligand and (R)-α-methylbenzylamine, by means of fractional, crystallisation is described. A full coordination study of palladium complexes containing 2pyridylphospholene and the corresponding phosphole ligands, both in solution (by means of NMR spectroscopy) and in the solid state (by X-ray diffraction), was carried out. These ligands were evaluated, in Pd-catalysed allylic substitution of racemic substrates (rac-3-acetoxy-l,3- diphenyl-l-propene and rac-3-acetoxy-l-cyclohexene) and (E)-3-acet-oxy-1-phenyl- 1-propene. A modelling study of the palladium allylic intermediates was performed, in order to justify the asymmetric induction observed with the 2-pyridylphospholene ligands.
- Leca, Francois,Fernandez, Fernando,Muller, Guillermo,Lescop, Christophe,Reau, Regis,Gomez, Montserrat
-
scheme or table
p. 5583 - 5591
(2010/06/15)
-
- Effective chiral ferrocenyl phosphine-thioether ligands in enantioselective palladium-catalyzed allylic alkylations
-
Chiral ferrocene-derived phosphine-thioether mixed donor ligands supported by heterocycles effected the palladium-catalyzed enantioselective allylic alkylations with excellent yields and enantioselectivities (up to 96% ee). With cyclic and unsymmetrical a
- Cheung, Hong Yee,Yu, Wing-Yiu,Au-Yeung, Terry T. L.,Zhou, Zhongyuan,Chan, Albert S. C.
-
experimental part
p. 1412 - 1422
(2009/12/22)
-
- Carbohydrate-Based Pyridine-2-carboxamides for Mo-Catalyzed asymmetric allylic alkylations
-
Bis(pyridine-2-carboxamides) were prepared from 1,2-di-amines obtained from α-D-glucose and α-D-mannose. The 11-gands were assessed in molybdenum-catalyzed asymmetric allylic alkylations (AAA) by using both methyl (E)-3-phenyl-2-propenyl and methyl rac-l-
- Del Litto, Raffaella,Benessere, Vincenzo,Ruffo, Francesco,Moberg, Christina
-
experimental part
p. 1352 - 1356
(2009/07/26)
-
- Ruthenium complexes bearing bulky pentasubstituted cyclopentadienyl ligands and evaluation of [Ru(η5-C5Me4R)(MeCN) 3][PF6] precatalysts in nucleophilic allylic substitution reactions
-
[Ru(η5-C5Me4R)(MeCN) 3][PF6] (R = CH2 tBu, iPr, tBu, and CF 3; 2-5) complexes were synthesized in two steps starting from the appropriate cyclopentadienes and RuCl3·3H2O. The fully substituted ruthenocenes [Ru(C5Me5)(C 5Me4R*)], [Ru(C5Me5)(C 5nPr4R*)] {R* = (1R,5S)-6,6-dimethylbicyclo- [3.1.1]hept-2-en-2-yl} and [Ru(C5Me5)(C 5nPr5)] were obtained by treating [Ru(C5Me 5)Cl]4 with the corresponding cyclopentadienyllithium salts. Complexes 2-5 were evaluated as catalyst precursors for nucleophilic allylic substitution reactions, and the results were compared to those obtained with the [Ru(C5Me5)(MeCN)3][PF6] (1) precatalyst. The etherification of p-methoxyphenol with the typical aliphatic chlorohexene allylic substrate shows that the introduction of the bulky tert-butyl and trifluoromethyl groups into the tetramethylcyclopentadienyl ring results in a valuable enhancement in regioselectivity in favour of the branched allyl aryl ether. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Zhang, Hui-Jun,Demerseman, Bernard,Xi, Zhenfeng,Bruneau, Christian
-
scheme or table
p. 3212 - 3217
(2009/02/07)
-
- Benzylic imidazolidinium, 3,4,5,6-tetrahydropyrimidinium and benzimidazolium salts: Applications in ruthenium-catalyzed allylic substitution reactions
-
Imidazolidinium, tetrahydropyrimidinium and benzimidazolium salts were prepared. Upon reaction with tBuOK, they generate carbene ligands, which were associated in situ to [RuCp*(MeCN)3]PF6 to produce ruthenium catalysts that are acti
- Yasar, Sedat,Oezdemir, Ismail,Cetinkaya, Bekir,Renaud, Jean-Luc,Bruneau, Christian
-
body text
p. 2142 - 2149
(2009/04/04)
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- Novel [ruthenium(substituted-tetramethylcyclopentadiene) (2-quinolinecarboxylato)(allyl)] hexafluorophosphate complexes as efficient catalysts for highly regioselective nucleophilic substitution of aliphatic allylic substrates
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Stable [ruthenium(R-substituted-tetramethylcyclopentadiene)(2- quinolinecarboxylato) (1-R′-substituted-allyl) hexafluorophosphate (R = Me, R′ = H, Me, n-Pr, Ph; R = t-Bu, R′ = Me) and [ruthenium(pentamethylcyclopentadiene)(2-quinolinecarboxylato)(1-n-propylallyl)] tetrafluoroborate (4′a), as allylruthenium(IV) complexes, have been synthesized in one step, starting from [ruthenium(R-substituted- tetramethylcyclopentadiene)tris(acetonitrile) hexafluorophosphate or tetrafluoroborate complexes, quinaldic acid, and allylic alcohols. Single stereoisomers are obtained and the X-ray single crystal structure determinations of 3b (R = t-Bu, R′ = Me) and 4′a allow one to specify the preferred arrangement. Complexes 3a (R = R′ = Me) and 3b are involved as precatalysts favoring the formation of branched products in regioselective nucleophilic allylic substitution reactions, starting from ethyl 2-(E)-hexen-1-yl carbonate and chlorohexene as unsymmetrical aliphatic allylic substrates. Phenols, dimethyl malonate, and primary (aniline) and secondary (pyrrolidine, piperidine) amines have been used as nucleophiles under mild basic conditions. For the first time, the regioselectivity in favor of the branched product obtained from purely aliphatic allylic substrates is close to the high regioselectivity previously reached starting from cinnamyl-type substrates in the presence of ruthenium catalysts.
- Zhang, Hui-Jun,Demerseman, Bernard,Toupet, Loic,Xi, Zhenfeng,Bruneau, Christian
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supporting information; experimental part
p. 1601 - 1609
(2009/07/18)
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- Iridium-catalyzed enantioselective allylic alkylation using chiral phosphoramidite ligand bearing an amide moiety
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New chiral phosphoramidites with an amide moiety were used for iridium-catalyzed asymmetric allylic alkylation reactions. The best results were obtained with a ligand bearing an oxazolidinone moiety. The reaction of cinnamyl acetate with diethyl sodiomalonate without the use of lithium chloride gave the branched product with 94% ee.
- Onodera, Gen,Watabe, Keijiro,Matsubara, Masaki,Oda, Kazuhiro,Kezuka, Satoko,Takeuchi, Ryo
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scheme or table
p. 2725 - 2732
(2009/11/30)
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- Iridium-catalyzed asymmetric allylic substitutions-very high regioselectivity and air stability with a catalyst derived from dibenzo[a,e]cyclooctatetraene and a phosphoramidite
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A final tweak: A new phosphoramidite iridium catalyst (see scheme) allows allylic substitutions to be run with a higher degree of regioselectivity than with other iridium catalysts and under aerobic conditions. Mechanistic aspects, in particular, the reversibility of the catalyst formation by C-H activation, are also presented. LL=dibenzocyclooctatetraene.
- Spiess, Stephanie,Welter, Carolin,Franck, Geraldine,Taquet, Jean-Philippe,Helmchen, Guenter
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supporting information; scheme or table
p. 7652 - 7655
(2009/04/11)
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- An efficient protocol of indium-catalyzed allylic substitution reaction and its application to polymer synthesis: Complementary regio- and stereoselective allylation polycondensation via Ir and Pd catalyses
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An efficient protocol of the Ir-catalyzed allylic substitution reaction is reported using N,O-bis(trimethylsilyl)acetamide as a base in the presence of nBu4NF as a cocatalyst. The reaction completely proceeded under very mild conditions, and a branched allylated compound that is not easy to access via the Tsuji-Trost reaction can be synthesized. The reaction system is practical enough to be applicable for polymer syntheses. The Ir- and Pd-catalyzed allylation polycondensations generally show complementary regio- and stereoselectivities. The Ir-catalyzed reaction is versatile, and a mixed dual regioselectivity such as a branched-linear selectivity on each electrophile can also be achieved. Copyright
- Nomura, Nobuyoshi,Komiyama, Susumu,Kasugai, Hiroyuki,Saba, Marie
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p. 812 - 814
(2008/09/20)
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- Features and applications of [Rh(CO)2Cl]2-catalyzed alkylations of unsymmetrical allylic substrates
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(Chemical Equation Presented) A novel regio- and stereoselective [Rh(CO)2Cl]2-catalyzed allylic alkylation of unsymmetrical allylic carbonates was discovered. The regioselectivity of the reaction favors product ratios in which substitution occurs at the carbon bearing the leaving group. When an enantiomerically enriched carbonate (≥99% ee) was examined, the Rh(I)-catalyzed allylic alkylation proceeded stereoselectively to provide the alkylation product with retention of absolute stereochemistry (98% ee). To establish the scope of the [Rh(CO)2Cl]2-catalyzed allylic alkylation, a variety of carbon and heteroatom nucleophiles were examined and the results described. As an application of the Rh(I)-catalyzed allylic alkylation, a series of novel domino reactions have been developed that couple the unique regio- and stereoselective [Rh(CO)2Cl]2- catalyzed alkylation of allylic trifluoroacetates with an intramolecular Pauson-Khand annulation, a cycloisomerization, or a [5+2] cycloaddition. A unique aspect of the method described is the use of a single catalyst to effect sequential transformations in which the catalytic activity is moderated simply by controlling the reaction temperature. Implementation of such processes provides a rapid and efficient entry to a variety of bicyclic carbon skeletons from simple precursors.
- Ashfeld, Brandon L.,Miller, Kenneth A.,Smith, Anna J.,Tran, Kristy,Martin, Stephen F.
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p. 9018 - 9031
(2008/03/13)
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- First allylpalladium systems containing chiral imidazolylpyridine ligands - Structural studies and catalytic behaviour
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Palladium/chiral imidazolylpyridine systems were tested in allylic alkylation of rac-3-acetoxy-1,3-diphenyl-1-propene (rac-I) and 3-acetoxy-1-phenyl-1-propene (II), paying particular attention to the influence of the amine nitrogen hybridisation on their catalytic behaviour. Allylpalladium complexes 9-11 containing optically pure imidazolines were synthesised and fully characterised both in solution (NMR) and the solid state (single-crystal X-ray diffraction). NMR studies showed four species in solution for complex 9 containing the unsymmetrical 1-phenylallyl group, while for 10 and 11, involving the symmetrical 1,3-diphenylallyl moiety, two species, endo and exo, were identified. In the solid state, only endo isomers crystallised for each complex. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Bastero, Amaia,Bella, Antonio F.,Fernandez, Fernando,Jansat, Susanna,Claver, Carmen,Gomez, Montserrat,Muller, Guillermo,Ruiz, Aurora,Font-Bardia, Merce,Solans, Xavier
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p. 132 - 139
(2007/10/03)
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- Ir-catalyzed asymmetric allylic alkylation using chiral diaminophosphine oxides: DIAPHOXs. Formal enantioselective synthesis of (-)-paroxetine
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An Ir-catalyzed asymmetric allylic alkylation using chiral diaminophosphine oxide is described. Asymmetric allylic alkylation of terminal allylic carbonates proceeded using 5 mol % of Ir catalyst, 5 mol % of DIAPHOX 1i, 10 mol % of NaPF6, 10 mo
- Nemoto, Tetsuhiro,Sakamoto, Tatsurou,Fukuyama, Takashi,Hamada, Yasumasa
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p. 4977 - 4981
(2008/02/09)
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- Phosphinooxazolines derived from 3-amino-1,2-diols: Highly efficient modular P-N ligands
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A family of chiral phosphinooxazolines (12a-e) derived from modular, enantiopure β-amino alcohols has been prepared, and their palladium complexes have been used as chiral mediators in the asymmetric allylic alkylation reaction. The oxazoline moiety in 12 contains a C-4 aryl and a C-5 alkoxymethyl substituent that can be independently optimized for high catalytic activity and enantioselectivity. A methoxymethyl substituent at C-5 has beenfound to provide the best results in terms of enantioselectivity and activity in the alkylation of a diverse family of allylic substrates under both thermal and microwave-assisted activation. The palladium-phos- phinooxazoline complexes described in this work are remarkably robust, as the enantioselectivity recorded in the asymmetric allylic alkylation remains essentially unchanged in the temperature range between 20 and 130°C. An unprecedented reversal in enantioselectivity has been observed between 1, 3-diphe-nylallyl and 1,3-dimethylallyl alkylation substrates, and the origin of this behavior has beeh explained by means of ONIOM QM/MM calculations.
- Popa, Dana,Puigjaner, Cristina,Gomez, Montserrat,Benet-Buchholz, Jordi,Vidal-Ferran, Anton,Pericas, Miquel A.
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p. 2265 - 2278
(2008/09/19)
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- Asymmetric allylic substitution catalyzed by C1-symmetrical complexes of molybdenum: Structural requirements of the ligand and the stereochemical course of the reaction
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Application of new chiral ligands (R)-(-)-12a and (S)-(+)-12c (VALDY), derived from amino acids, to the title reaction, involving cinnamyl (linear) and isocinnamyl (branched) type substrates (4 and 5 → 6), led to excellent regio- and enantioselectivities (>30:1, ≤98% ee), showing that ligands with a single chiral center are capable of high asymmetric induction. The structural requirements of the ligand and the mechanism are discussed. The application of single enantiomers of deuterium-labeled substrates (both linear 38c and branched 37c) and analysis of the products (41-43) by 2{ 1H) NMR spectroscopy in a chiral liquid crystal matrix allowed the stereochemical pathways of the reaction to be distinguished. With ligand (S)-(+)-12c, the matched enantiomer of branched substrate was found to be (S)-5, which was converted into (R)-6 with very high regio- and stereoselectivity via a process that involves net retention of stereochemistry. The mismatched enantiomer of the branched substrate was found to be (R)-5, which was also converted into (R)-6, that is, with apparent net inversion, but at a lower rate and with lower overall enantioselectivity. This latter feature, which may be termed a "memory effect", reduced the global enantioselectivity in the reaction of the racemic substrate (±)-5. The stereochemical pathway of the mismatched manifold has been shown also to be one of net retention, the apparent inversion occurring through equilibration via an Mo-allyl intermediate prior to nucleophilic attack. Incomplete equilibration leads to the memory effect and thus to lower enantioselectivity. Analysis of the mismatched manifold over the course of the reaction revealed that the memory effect is progressively attenuated with the nascent global selectivity increasing substantially as the reaction proceeds. The origin of this effect is suggested to be the depletion of CO sources in the reaction mixture, which attenuates turnover rate and thus facilitates greater equilibrium. The linear substrate was also converted into the branched product with net syn stereochemistry, as shown by isotopic labeling. An analogous process operates in the generation of small quantities of linear product from branched substrate.
- Malkov, Andrei V.,Gouriou, Laure,Lloyd-Jones, Guy C.,Stary, Ivo,Langer, Vratislav,Spoor, Paul,Vinader, Victoria,Kocovsky, Pavel
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p. 6910 - 6929
(2007/10/03)
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- Phosphoramidite ligands in iridium-catalyzed allvlic substitution
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A new phosphoramidite ligand was used in the iridium-catalyzed allylic substitution reaction. This permitted high regio- and enantioselectivities on a wide variety of substrates and nucleophiles. Because of the stereospecificity of the reaction obtained by using branched substrates, a kinetic resolution reaction was attempted. The origin of the impressive efficiency of this ligand in terms of kinetics was explored in detail, as was the role of the substituent in the ortho-position of the amine moiety.
- Polet, Damien,Alexakis, Alexandre,Tissot-Croset, Karine,Corminboeuf, Clemence,Ditrich, Klaus
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p. 3596 - 3609
(2008/02/04)
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- Regioselectivity with hemispherical chelators: Increasing the catalytic efficiency of complexes of diphosphanes with large bite angles
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(Chemical Equation Presented) Control through molecular pockets: Calixarene-derived diphosphites provide effective hemispherical crowding about catalytic centers. When used in the palladium-catalyzed alkylation of cinnamyl acetate, regioselectivities higher than 98% in favor of the linear product are observed. In the rhodium-catalyzed hydroformylation of styrene, these diphosphites lead to phenylpropionaldehyde with selectivities as high as 76%.
- Semeril, David,Jeunesse, Catherine,Matt, Dominique,Toupet, Loic
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p. 5810 - 5814
(2007/10/03)
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- Sequential catalytic isomerization and allylic substitution. Conversion of racemic branched allylic carbonates to enantioenriched allylic substitution products
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A catalytic protocol for the conversion of readily accessible racemic, branched aromatic allylic esters to branched allylic amines, ethers, and alkyls has been developed. Palladium-catalyzed isomerization of branched allylic esters to terminal allylic esters, followed by sequential iridium-catalyzed allylic substitution, gave the branched allylic products in good yield with high regioisomeric and enantiomeric selectivity. Both electron-rich and electron-poor branched allylic esters gave products in >90% ee. High enantiomeric excesses were also observed for the products from the reactions of 2-thienyl acetates and dienyl carbonates. Copyright
- Shekhar, Shashank,Trantow, Brian,Leitner, Andreas,Hartwig, John F.
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p. 11770 - 11771
(2007/10/03)
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- Furanoside thioether-phosphinite ligands for Pd-catalyzed asymmetric allylic substitution reactions: Scope and limitations
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A series of readily available thioether-phosphinite ligands has been tested in the Pd-catalyzed allylic substitution reactions of several acyclic and cyclic allylic substrates (S1-S7). This series of ligands have been designed to uncover their important s
- Diéguez, Montserrat,Pàmies, Oscar,Claver, Carmen
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p. 2257 - 2262
(2007/10/03)
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- A highly regioselective salt-free iron-catalyzed allylic alkylation
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(Chemical Equation Presented) Ironing out the kinks: A highly regioselective allylic alkylation can be performed in the presence of catalytic amounts of an iron(-II) complex and triphenylphosphane (see scheme; EWG = electron-withdrawing group). Allyl carbonates and pronucleophiles are coupled in high yields with a high regioselectivity comparable only with that obtained with Rh catalysts. The reaction is broadly applicable and does not require external base.
- Plietker, Bernd
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p. 1469 - 1473
(2007/10/03)
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- Regioselective allylic alkylation and etherification catalyzed by in situ generated N-heterocyclic carbene ruthenium complexes
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Benzimidazolium halides are used for the first time as ligand precursors in ruthenium-catalyzed substitution of allylic carbonates and chlorides by carbon nucleophiles and phenols, respectively. After generation of diaminocarbene species upon deprotonatio
- Gürbüz, Nevin,?zdemir, Ismail,?etinkaya, Bekir,Renaud, Jean-Luc,Demerseman, Bernard,Bruneau, Christian
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p. 535 - 538
(2007/10/03)
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- Chiral bis(N-sulfonylamino)phosphine- and TADDOL-phosphite-oxazoline ligands: Synthesis and application in asymmetric catalysis
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A series of N,P-ligands has been prepared, containing a chiral oxazoline ring and as a second chiral unit a bis(N-sulfonylamino)phosphine group embedded in a diazaphospholidine ring or a cyclic phosphite group derived from TADDOL. These modular ligands are readily synthesized from chiral amino alcohols and chiral 1,2-diamines or TADDOLs. Palladium and iridium complexes derived from these ligands were found to be efficient catalysts for enantioselective allylic alkylation and olefin hydrogenation, respectively.
- Hilgraf, Robert,Pfaltz, Andreas
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