- Carbamate-based P,O-ligands for asymmetric allylic alkylations
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Herein we report the design and successful catalytic application of modified Trost-ligands in asymmetric allylic alkylation (AAA) reactions. A small set of carbamate-monophosphine P,O-ligands has been prepared in a straightforward two-step synthetic procedure. After optimization of the reaction conditions, high catalytic activities and excellent enantioselectivity up to >99% have been attained.
- Pálv?lgyi, ádám Márk,Schnürch, Michael,Bica-Schr?der, Katharina
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- An improved class of phosphite-oxazoline ligands for Pd-catalyzed allylic substitution reactions
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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
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p. 6033 - 6048
(2019/07/19)
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- A readily accessible and modular carbohydrate-derived thioether/selenoether-phosphite ligand library for Pd-catalyzed asymmetric allylic substitutions
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A large library of thioether/selenoether-phosphite ligands have been tested in the Pd-catalyzed asymmetric allylic substitution reaction. The presented ligands are derived from cheap and available carbohydrates and they are air-stable solids and easy to handle. Their highly modular nature has made it possible to achieve excellent enantioselectivities in the substitution of a range of hindered and unhindered substrates (ees up to 99% and 91%, respectively). In addition, twelve C-, N- and O-nucleophiles can be efficiently introduced, independently of their nature. Among the whole library, ligands that contain an additional chiral centre in the alkyl backbone chain next to the phosphite group and an enantiopure biaryl phosphite group provided the best enantioselectivities. In general, there is a cooperative effect between these two chiral elements, and therefore, a matched combination between them is necessary to achieve the highest enantioselectivities. However, in the case of cyclic substrates, this cooperative effect is less pronounced and advantageously, both enantiomers of the product can be obtained by setting up the desired configuration of the biaryl phosphite group. Studies of the key Pd-π-allyl intermediates allowed us to better understand the enantioselectivities obtained experimentally.
- Margalef, Jèssica,Borràs, Carlota,Alegre, Sabina,Pàmies, Oscar,Diéguez, Montserrat
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supporting information
p. 12632 - 12643
(2019/08/26)
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- Ligand's electronegativity controls the sense of enantioselectivity in BIFOP-X palladium-catalyzed allylic alkylations
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Palladium-catalyzed allylic alkylations of sodium dimethyl malonate with 1,3-diphenylallyl acetate, employing BIFOP-H (biphenylbisfencholphosphite) and analogue (i.e. BIFOP-X, X = D, Cl, CN, N3) ligands, all yield (S)-enantiomeric products, while alkylations to cyclohexenyl acetate yield the (R)-enantiomeric C-C coupling product (up to 91% yield, 70% ee). The fluoro derivative BIFOP-F however, "switches" the sense of enantioselectivity, yielding the (R)-enantiomer for 1,3-diphenylallyl acetate and the (S)-enantiomer for the cyclohexenyl acetate (up to 92% yield, 67% ee). Computational analyses of transition structures (M06-2X-D3/def2-TZVP//B3LYP-D3(BJ)/def2-SVP) for these Pd-catalyzed allylic alkylations reproduce the experimental preference of BIFOP-H (and analogue BIFOP-X ligands) for (R)- or (S)-enantiomeric products of 1,3-diphenylallyl or cyclohexenyl acetate, respectively. The "F-switch" of the sense of enantioselectivity from BIFOP-H to BIFOP-F is also apparent computationally and is found (NBO-analyses) to originate from lp(Pd) → σ?(P-O) or lp(Pd) → σ?(P-F) hyperconjugations. The higher electronegativity of F vs. H in BIFOP-X hence controls the sense of enantioselectivity of this Pd-catalyzed allylic alkylation.
- Brüllingen, Eric,Neud?rfl, J?rg-Martin,Goldfuss, Bernd
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supporting information
p. 15743 - 15753
(2019/10/19)
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- A protic ionic liquid as an atom economical solution for palladium catalyzed asymmetric allylic alkylation
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The asymmetric allylic alkylation of rac-1,3-diphenyl-3-acetoxyprop-1-ene (I) catalysed by palladium and diverse phosphorus containing ligands [(S)-BINAP, (R,R)-Chiraphite and (R,R)-Et-Duphos] in an ionic liquid [HDBU][OAc] was successfully performed, ach
- Guerrero-Ríos, Itzel,Ortiz-Ramírez, Alfonso H.,Van Leeuwen, Piet W. N. M.,Martin, Erika
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p. 3739 - 3744
(2018/03/21)
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- Computationally guided design of a readily assembled phosphite-thioether ligand for a broad range of pd-catalyzed asymmetric allylic substitutions
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A modular approach employing indene as common starting material, has enabled the straightforward preparation in three reaction steps of P-thioether ligands for the Pd-catalyzed asymmetric allylic substitution. The analysis of a starting library of P-thioether ligands based on rational design and theoretical calculations has led to the discovery of an optimized anthracenethiol derivative with excellent behavior in the reaction of choice. Improving most approaches reported to date, this ligand presents a broad substrate and nucleophile scope. Excellent enantioselectivities have been achieved for a range of linear and cyclic allylic substrates using a large number of C-, N-, and O-nucleophiles (40 compounds in total). The species responsible for the catalytic activity have been further investigated by NMR in order to clearly establish the origin of the enantioselectivity. The resulting products have been derivatized by means of ring-closing metathesis or Pauson-Khand reactions to further prove the synthetic versatility of the methodology for preparing enantiopure complex structures.
- Biosca, Maria,Margalef, Jèssica,Caldentey, Xisco,Besora, Maria,Rodríguez-Escrich, Carles,Saltó, Joan,Cambeiro, Xacobe C.,Maseras, Feliu,Pàmies, Oscar,Diéguez, Montserrat,Pericàs, Miquel A.
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p. 3587 - 3601
(2018/04/14)
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- Amino-P Ligands from Iminosugars: New Readily Available and Modular Ligands for Enantioselective Pd-Catalyzed Allylic Substitutions
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The construction of a novel class of amino-phosphite/phosphinite/phosphine ligands containing a protected pyrrolidine-3,4-diol moiety is presented. These ligands are obtained from readily available sugars. They thus contain the advantages of carbohydrates in terms of selection of the stereogenic carbons, polyfunctional groups able to modulate the electronic and steric properties, and the general good stability of carbohydrate derivatives. They constitute a novel class of P,N-ligands that have been used in the enantioselective allylic substitutions of acyclic and cyclic substrates with varied electronic and steric requirements, using different C- and N-nucleophiles, with high enantioselectivities. Among the three groups of P,N-ligands (amino-P; P = phosphite, phosphinite, and phosphine groups) the new amino-phosphite ligands give the widest substrate and nucleophile scope, including the more challenging hindered linear and cyclic substrates. In particular, for carbohydrate-derived amino-phosphite ligands and linear substrates, high enantioselectivity in the reactions requires an R configuration of the binaphthyl moiety. However, for cyclic substrates both product enantiomers can be reached by setting out the chirality of the binaphthyl phosphite moiety. A detailed investigation of the appropriate Pd intermediates is also presented.
- Borràs, Carlota,Elías-Rodríguez, Pilar,Carmona, Ana T.,Robina, Inmaculada,Pàmies, Oscar,Diéguez, Montserrat
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p. 1682 - 1694
(2018/06/18)
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- Palladium allylic complexes with enantiopure bis(diamidophosphite) ligands bearing a cyclohexane-1,2-diamine skeleton as catalysts in the allylic substitution reaction
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A series of cationic allyl palladium complexes [Pd(η3-CH3-C3H5)(P-P)]X (X = PF6, 2a-c, 2e; and X = BPh4, 3a, 3b, 3d, 3e) and [Pd(η3-1,3-Ph2-C3H3)
- Bravo, Maritza J.,Ceder, Rosa M.,Grabulosa, Arnald,Muller, Guillermo,Rocamora, Mercè,Font-Bardia, Mercè
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- NeoPHOX - A structurally tunable ligand system for asymmetric catalysis
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A synthesis of new NeoPHOX ligands derived from serine or threonine has been developed. The central intermediate is a NeoPHOX derivative bearing a methoxycarbonyl group at the stereogenic center next to the oxazoline N atom. The addition of methylmagnesiu
- Padevět, Jaroslav,Schrems, Marcus G.,Scheil, Robin,Pfaltz, Andreas
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supporting information
p. 1185 - 1195
(2016/07/06)
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- Cofactor-Controlled Chirality of Tropoisomeric Ligand
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A new tropos ligand with an integrated anion receptor site has been prepared. Chiral carboxylate and phosphate anions that bind in the anion receptor unit proved capable of stabilizing chiral conformations of the achiral flexible bidentate biaryl phosphite ligand, as shown by variable temperature 1H and 31P NMR spectroscopical studies of palladium(0) olefin complexes. Palladium allyl complexes of the supramolecular ligand-chiral cofactor assemblies catalyzed asymmetric allylic substitutions of rac-(E)-1,3-diphenyl-2-propenyl carbonate and rac-3-cyclohexenyl carbonate with malonate and benzylamine as nucleophiles to provide nonracemic products. Although moderate enantioselectivities were observed, (ee:s up to 66%), the results confirm the ability of the anionic guests to affect the conformation of the ligand.
- Théveau, Laure,Bellini, Rosalba,Dydio, Pawe?,Szabo, Zoltan,Van Der Werf, Angela,Afshin Sander, Robin,Reek, Joost N. H.,Moberg, Christina
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supporting information
p. 1956 - 1963
(2016/07/06)
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- Conformational Preferences of a Tropos Biphenyl Phosphinooxazoline-a Ligand with Wide Substrate Scope
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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
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p. 1701 - 1712
(2016/03/15)
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- Asymmetric catalyzed allylic substitution using a Pd/P-S catalyst library with exceptional high substrate and nucleophile versatility: DFT and Pd-π-allyl key intermediates studies
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A large library of furanoside phosphite/phosphinite/phosphine-thioether ligands L1-L17a-l has been applied in the Pd-catalyzed allylic substitution reactions of several substrate types using a wide range of nucleophiles. These ligands, which are prepared from inexpensive d-xylose, also incorporate the advantages of the heterodonor, the robustness of the thioether moiety, and the extra control provided by the flexibility of the chiral pocket through the presence of a biaryl phosphite group and a modular sugar backbone. By selecting the ligand components, we have been able to identify catalytic systems that can create new C-C, C-N, and C-O bonds in several substrate types (hindered and unhindered) using a wide range of nucleophiles in high yields and enantioselectivities (ee's up to >99%). Of particular note are the excellent enantioselectivities obtained in the etherification of linear and cyclic substrates, which represent the first example of successful etherification of both substrate types. The DFT computational study is in agreement with an early transition state. Further studies on the Pd-π-allyl intermediates provided a deep understanding of the effect of ligand structure in the origin of enantioselectivity.
- Margalef, Jèssica,Coll, Mercè,Norrby, Per-Ola,Pàmies, Oscar,Diéguez, Montserrat
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p. 3323 - 3335
(2016/10/21)
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- Chiral wide-bite-angle diphosphine ligands: Synthesis, coordination chemistry, and application in Pd-catalyzed allylic alkylation
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A series of diphosphine ligands bearing ester- and ether-modified diphenylether backbones have been prepared. The introduction of carboxylic acid or ether auxiliaries in the ortho-positions relative to the diphenylphosphine groups was achieved via straigh
- Czauderna, Christine F.,Jarvis, Amanda G.,Heutz, Frank J.L.,Cordes, David B.,Slawin, Alexandra M.Z.,Van Der Vlugt, Jarl Ivar,Kamer, Paul C.J.
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p. 1608 - 1618
(2015/05/20)
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- Modular P-Chirogenic Phosphine-Sulfide Ligands: Clear Evidence for Both Electronic Effect and P-Chirality Driving Enantioselectivity in Palladium-Catalyzed Allylations
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Using the ephedrine methodology, modular stereoselective syntheses of a new class of P-chirogenic phosphines bearing a sulfur-chelating arm (P?,S-hybrid ligand) are described. A first series of syntheses based on a Fries-like rearrangement of P-chirogenic phosphinite-boranes, which are prepared from 2-bromobenzyl or 2-bromophenethyl alcohol and are mediated by metal-halide exchange, have been performed. This rearrangement affords phosphine-boranes stereospecifically with an o-hydroxyalkylphenyl substituent. The latter residue is subsequently converted into a sulfur-containing group. In a second series, the stereoselective syntheses were achieved according to a new strategy involving a reaction of a thiophenyllithium reagent with a P-chirogenic phosphinite. The X-ray structures of the P?,S ligands and their palladium complexes allow us to address the absolute configuration at both the phosphorus and sulfur centers. The P?,S ligands were used in palladium-catalyzed allylic alkylations, as tests, affording asymmetric inductions up to 96% ee. Computer modeling corroborates the regio- and enantioselectivity of the Pd-catalyzed allylations and the low influence of the substituent carried by the sulfur moiety, particularly when the chelate forms a six-membered ring with the metal.
- Bayardon, Jér?me,Maronnat, Milène,Langlois, Adam,Rousselin, Yoann,Harvey, Pierre D.,Jugé, Sylvain
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p. 4340 - 4358
(2015/09/22)
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- Theoretical and Experimental Optimization of a New Amino Phosphite Ligand Library for Asymmetric Palladium-Catalyzed Allylic Substitution
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A new library of modular amino phosphite ligands obtained in a few synthetic steps from enantiopure amino alcohols has been tested in asymmetric Pd-catalyzed allylic substitution. The modular ligand design is crucial to find highly selective catalysts for each substrate type using a wide range of C-, N-, and O-nucleophiles. A DFT study of the species responsible for the enantiocontrol was used to optimize the ligand structure. By selecting the ligand components, we were able to identify unprecedented catalytic systems that can create new chiral C-C, C-N, and C-O bonds in a variety of substrate types (hindered and unhindered) in high yields and enantioselectivities (ee values up to 99 %). Further studies on the Pd-π-allyl intermediates provided a deep understanding of the effect of ligand structure in the origin of enantioselectivity. Potential applications of the new Pd/amino phosphite catalysts were demonstrated by the practical synthesis of a range of chiral carbocycles by simple tandem reactions, with no loss of enantioselectivity.
- Magre, Marc,Biosca, Maria,Norrby, Per-Ola,Pàmies, Oscar,Diéguez, Montserrat
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p. 4091 - 4107
(2015/12/26)
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- Palladium-catalyzed enantioselective allylic substitution in the presence of monodentate furanoside phosphoramidites
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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)
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- A new type of ferrocene-based phosphine-tert-butylsulfinamide ligand: Synthesis and application in asymmetric catalysis
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A new type of ferrocene-based phosphine-tert-butylsulfinamide ligand has been synthesized and applied to the enantioselective formation of C-C and C-N bonds. The palladium complex derived from ligand 4a was an efficient catalyst in asymmetric allylic substitution of several substrate types. Enantioselectivites with the difficult substrate 3-acetoxycyclohexene of up to 91% ee are achieved.
- Ma, Jiangwei,Li, Chuang,Zhang, Dongxu,Lei, Yang,Li, Muqiong,Jiang, Ru,Chen, Weiping
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p. 35888 - 35892
(2015/05/05)
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- Sterically demanding planar chiral P,N ligands by diastereoselective ortho lithiation of pentaphenylferrocenyloxazolines and their application to palladium-catalyzed substitutions with cyclic allylic acetates
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Functionalized 1′,2′,3′,4′,5′- pentaphenylferrocenes are known as valuable ligands and catalysts. Planar chiral derivatives - e.g. Fu's pentaphenylferrocene fused pyridines or palladacycles developed in our group - have previously been described to be very efficient asymmetric catalysts for a number of applications. Nevertheless, protocols for diastereoselective ortho lithiations of 1′,2′,3′,4′, 5′-pentaphenylferrocenes are still unknown. Such protocols could significantly increase the arsenal of accessible planar chiral pentaphenylferrocenes. In this full paper, we describe such diastereoselective ortho lithiations of pentaphenylferrocenyloxazolines. Both possible diastereomers can be produced in almost diastereomerically pure form depending on the choice of a Lewis base additive, which is required in the lithiation step for a sufficient reactivity. This development was utilized to prepare a set of planar chiral pentaphenylferrocene-based phosphino-oxazoline ligands. The latter were investigated in Pd-catalyzed allylic substitution reactions with cyclic allylic acetates to allow for a first comparison with related planar chiral ligands and provided good enantioselectivity with this challenging substrate class.
- Ayerbe Garcia, Marta,Frey, Wolfgang,Peters, Rene
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p. 1068 - 1078
(2014/03/21)
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- Highly versatile Pd-thioether-phosphite catalytic systems for asymmetric allylic alkylation, amination, and etherification reactions
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A Pd-furanoside thioether-phosphite catalytic system that can create new C-C, C-N, and C-O bonds in several substrate types using a wide range of nucleophiles in high yields and enantioselectivities has been identified. Of particular note are the excellent enantioselectivities obtained in the etherification of linear and cyclic substrates. The potential application of the new Pd-thioether-phosphite catalytic systems was also demonstrated by the synthesis of the chiral carbo- and heterocycles.
- Coll, Merce,Pamies, Oscar,Dieguez, Montserrat
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supporting information
p. 1892 - 1895
(2014/05/06)
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- A new modular phosphite-pyridine ligand library for asymmetric Pd-catalyzed allylic substitution reactions: A study of the key Pd-π-allyl intermediates
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A library of phosphite-pyridine ligands L1-L12 a-g has been successfully applied for the first time in the Pd-catalyzed allylic substitution reactions of several di- and trisubstituted substrates by using a wide range of C, N and O nucleophiles, among which are the little studied α-substituted malonates, β-diketones, and alkyl alcohols. The highly modular nature of this ligand library enables the substituents/configuration at the ligand backbone, and the substituents/configurations at the biaryl phosphite moiety to be easily and systematically varied. We found that the introduction of an enantiopure biaryl phosphite moiety played an essential role in increasing the versatility of the Pd-catalytic systems. Enantioselectivities were therefore high for several hindered and unhindered di- and trisubstituted substrates by using a wide range of C, N and O nucleophiles. Of particular note were the high enantioselectivities (up to>99 % ee) and high activities obtained for the trisubstituted substrates S6 and S7, which compare favorably with the best that have been reported in the literature. We have also extended the use of these new catalytic systems in alternative environmentally friendly solvents such as propylene carbonate and ionic liquids. Studies on the Pd-π-allyl intermediates provide a deeper understanding of the effect of ligand parameters on the origin of enantioselectivity. A library of phosphite-pyridine ligands has been successfully applied in the Pd-catalyzed allylic substitution reactions of several di- and trisubstituted substrates by using a wide range of C, N, and O nucleophiles. By carefully selecting the ligand components, high regio- and enantioselectivities (up to >99 % ee) and good activities have been achieved (see scheme). The NMR studies on the Pd-π-allyl intermediates provide a deeper understanding of the effect of ligand parameters on the origin of enantioselectivity. Copyright
- Mazuela, Javier,Pàmies, Oscar,Diéguez, Montserrat
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supporting information
p. 2416 - 2432
(2013/04/23)
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- CYCLIC IMIDATE LIGANDS
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The present invention relates to a use of a cyclic imidate as a ligand for catalysis in which the ligand contains sub-structure (Y) as a minimal structural motive, wherein the carbon atoms and the nitrogen atom can be optionally substituted by a chemical substituent.
- -
-
Page/Page column 22-23
(2012/04/05)
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- Synthesis of a novel C2-symmetric bis-oxazoline (=bis[4,5-dihydrooxazole]) and its application as chiral ligand in asymmetric transition metal catalysis
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The new C2-symmetric bis-oxazoline (=bis[4,5-dihydrooxazole]) 2 with a chiral trans-(2R,3R)-2,3-bis(3,5-diphenylphenyl)cyclopropylidene (=trans-(2R,3R)-2,3-bis([1,1′: 3′,1″-terphenyl]-5′-yl) cyclopropylidene) backbone was efficiently synthesized (Scheme). All synthetic steps were easy to perform and led to the desired product in good overall yields. Compound 2 was tested and compared as ligand in several enantioselective catalytic reactions such as palladium(0)-catalyzed enantioselective allylic alkylations and copper(I)-catalyzed enantioselective cyclopropanations and aziridinations. Copyright
- Goek, Yasar,Van Der Eycken, Johan
-
experimental part
p. 831 - 838
(2012/06/16)
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- Evaluation of phosphinoamidoester-derived Pd catalysts in the asymmetric allylic alkylation reaction: Theoretical studies and mechanistic insights
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Two simple hemilabile P,O-coordinating phosphinoamidoester ligands 6a and 6b were synthesized and studied in the Pd(0)-catalyzed asymmetric allylic alkylation of rac-1,3-diphenylpropenyl acetate affording a highest ee of 83% ee with 6a. To gain an insight
- Marinho, Vanda R. D.,Ramalho, J.P.Prates,Rodrigues, Ana Isabel,Burke, Anthony J.
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experimental part
p. 383 - 388
(2012/01/05)
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- Pd-catalyzed asymmetric reactions using resorcinol- and hydroquinone-based P,P-bidentate diamidophosphites
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Readily available isomeric bisdiamidophosphites with P-stereocentres have been prepared using resorcinol and hydroquinone as simple and cheap starting materials. Palladium catalytic systems containing these P,P-bidentate ligands afforded 99% and 70% ees i
- Gavrilov, Konstantin N.,Zheglov, Sergey V.,Shiryaev, Alexei A.,Groshkin, Nikolay N.,Rastorguev, Eugenie A.,Benetskiy, Eduard B.,Davankov, Vadim A.
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supporting information; experimental part
p. 964 - 968
(2011/03/20)
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- Synthesis of phosphorylated sulfoximines and sulfinamides and their application as ligands in asymmetric metal catalysis
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Starting from inexpensive materials and following simple protocols various N-phosphorylated sulfoximines and sulfinamides have been synthesized. The newly prepared compounds were then applied as chiral ligands in asymmetric transition metal catalysis. Pho
- Benetskiy, Eduard B.,Bolm, Carsten
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scheme or table
p. 373 - 378
(2011/05/06)
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- A new class of modular P,N-ligand library for asymmetric Pd-catalyzed allylic substitution reactions: A study of the key Pd-π- allyl intermediates
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A new class of modular P,N-ligand libary has been Synthesized and screened in the pd-catalyzed allylic substitution reaction of several substrate types. These series of ligands can be prepared efficiently from easily accessible hydroxyle - oxazale/ thiazale de-rivatives. modular nature enables the bridge, the substituents at teh hetro cyclic ring and in the alkyl back bone chain, the configuration of the ligand backbone, and the substituents/configurations in the biaryl phosphite moiety to be easily and systematically varied. By carefully selecting the ligand components, therefore, high regio- and enantioselectivities (ee values up to 96%) and good activities are achieved in a broad range of mono-, di-, and trisubstituted linear hindered and unhindered substrates and cyclic substrates. The NMR spectroscopic and DFT studies on the Pdπ-allyl intermediates provide a deeper understanding of the effect of ligand parameters on the origin of enantioselectivity.
- Mazuela, Javier,Paptchikhine, Alexander,Tolstoy, Paeivi,Pamies, Oscar,Dieguez, Montserrat,Andersson, Pher G.
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experimental part
p. 620 - 638
(2010/06/12)
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- Synthesis of phosphanyl sulfoximines through phospha-michael reaction of alkenyl sulfoximines and their evaluation as chiral bidentate 1, 5-N, P ligands for palladium in asymmetric allylic alkylation
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The intermolecular phospha-Michael reaction of cyclic and acyclic alkenyl sulfoximines proceeds readily and yields the corresponding phosphanyl sulfoximines in good yield. The asymmetric induction provided, by sulfoximine group in C-P bond formation is ap
- Lemasson, Fabien,Gais, Hans-Joachim,Runsink, Jan,Raabe, Gerhard
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experimental part
p. 2157 - 2175
(2010/06/16)
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- Imidate-phosphanes as highly versatile N,P Ligands and their application in palladium-catalyzed asymmetric allylic alkylation reactions
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Chiral imidate-phosphanes were developed as a new type of N,P ligands. These ligands are easily accessible through a one-step procedure starting from a commercially available chiral aminophosphane and an imidate precursor. Excellent performance of the cat
- Noel, Timothy,Bert, Katrien,Van Der Eycken, Erik,Van Der Eycken, Johan
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supporting information; experimental part
p. 4056 - 4061
(2010/09/18)
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- A modular approach to a new class of phosphinohydrazones and their use in asymmetric allylic alkylation reactions
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A group of five phosphino hydrazones with a pendant binaphthyl unit as a chiral modifier has been synthesized from non-racemic 2,2′- bis(bromomethyl)-1,1′-binaphthyl and 3,3′-diiodo-2,2′- bis(bromomethyl)-1,1′-binaphthyl as the key intermediates. Their efficiency as chiral ligands in palladium-catalyzed allylic alkylation reactions has been investigated showing up to 95% ee under optimized conditions. X-ray diffraction structures of mono- and dimeric Pd complexes are also reported.
- Widhalm, Michael,Abraham, Michael,Arion, Vladimir B.,Saarsalu, Siret,Maeorg, Uno
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experimental part
p. 1971 - 1982
(2010/10/18)
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- Novel C2-symmetric bisoxazolines with a chiral trans-(2R,3R)-diphenylcyclopropane backbone: Preparation and application in several enantioselective catalytic reactions
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Various chiral bisoxazoline ligands with a chiral trans-(2R,3R)- diphenylcyclopropane backbone have been efficiently synthesized (five examples). These chiral ligands were tested and compared in palladium(0)-catalysed enantioselective allylic alkylations
- Goek, Yaar,Noel, Timothy,Van Der Eycken, Johan
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experimental part
p. 2275 - 2280
(2010/11/03)
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- Modular chiral diphosphite derived from l-tartaric acid. Applications in metal-catalyzed asymmetric reactions
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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
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experimental part
p. 68 - 75
(2010/11/05)
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- Norbornene bidentate ligands: coordination chemistry and enantioselective catalytic applications
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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
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experimental part
p. 758 - 766
(2010/06/12)
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- Asymmetric catalytic reactions using P*-mono-, P*,N- and P*,P*-bidentate diamidophosphites with BINOL backbones and 1,3,2-diazaphospholidine moieties: Differences in the enantioselectivity
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A new series of P*-chiral diamidophosphites with 1,3,2- diazaphospholidine rings, based on (Sa)- or (Ra)-BINOL and their easily accessible derivatives, has been synthesized for the first time and tested in asymmetric transition metal catalysis. Up to 99% ee was achieved in the rhodium-catalyzed asymmetric hydrogenation of functionalized olefins and in the palladium-catalyzed allylic substitution. The influence of the nature of the donor atoms and denticity on the asymmetric induction is discussed. In addition, the first example of a successful platinum-catalyzed asymmetric allylic amination (up to 86% ee) with participation of organophosphorus ligands is considered.
- Gavrilov, Konstantin N.,Zheglov, Sergey V.,Rastorguev, Eugenie A.,Groshkin, Nikolay N.,Maksimova, Marina G.,Benetsky, Eduard B.,Davankov, Vadim A.,Reetz, Manfred T.
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supporting information; experimental part
p. 2599 - 2610
(2011/01/05)
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- Palladium-catalyzed allylic substitution assisted by 1,3,2- diazaphospholidine derivatives of (R,R)-N-naphthyltartarimide
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P,P-Bidentate diamidophosphite ligands containing the (3R,4R)-3,4-dioxy-1- (1-naphthyl)pyrrolidine-2,5-dione framework and 1,3,2-diazaphospholidine rings with the stereogenic P atoms were obtained. The use of these ligands provides up to 85% ee in Pd-cata
- Gavrilov,Rastorguev,Zheglov,Groshkin,Boyko,Safronov,Petrovskii,Davankov
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experimental part
p. 1242 - 1247
(2011/02/23)
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- Influence of structural changes in ferrocene phosphane aminophosphane ligands on their catalytic activity
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New phosphane aminophosphane ligands based on [3]ferrocenophane skeleton were synthesized using a direct double lithiation followed by phosphanylation. Influence of ligand structure on catalytic performance was evaluated by performing a series of Pd-catalyzed allylic substitution on different substrates. Enantioselectivities up to 55% ee were obtained with bridged ligand compared to 33% ee with analogous non-bridged BoPhoz ligand.
- ?ebesta, Radovan,?kvorcová, Andrea
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experimental part
p. 1898 - 1902
(2009/10/01)
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- Effective chiral ferrocenyl phosphine-thioether ligands in enantioselective palladium-catalyzed allylic alkylations
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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.
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experimental part
p. 1412 - 1422
(2009/12/22)
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- Pyranoside phosphite-oxazoline ligand library: Highly efficient modular P,N ligands for palladium-catalyzed allylic substitution reactions. A study of the key palladium allyl intermediates
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We have screened a library of modular phosphite-oxazoline ligands for asymmetric allylic substitution reactions. The library is efficiently prepared from the commercially available and cheap dglucosamine. The introduction of a phosphite moiety into the ligand design is highly advantageous for the product outcome. Therefore, this ligand library affords good-to-excellent reaction rates [TOFs up to 600 mol substrate × (mol Pd × h)-1] and enantioselectivities (ees up to 99%) and, at the same time, shows a broad scope for mono-, di-and trisubstituted linear hindered and unhindered substrates and cyclic substrates. The NMR studies on the palladium allyl intermediates provide a deeper understanding about the effect of the ligand parameters on the origin of enantioselectivity.
- Mata, Yvette,Pamies, Oscar,Dieguez, Montserrat
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experimental part
p. 3217 - 3234
(2010/04/28)
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- Application of Walphos ligand in the Pd(0)-catalyzed asymmetric allylic alkylation reaction
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One relatively unexploited commercial ligand, Walphos 1, was tested in the Pd(0)-catalyzed asymmetric allylic alkylation using rac-1,3-diphenyl propenyl acetate and rac-1-acetoxycyclohexene as substrates, methyl malonate as nucleophile, and a variety of P
- Marinho, Vanda R.,Burke, Anthony J.
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experimental part
p. 4423 - 4428
(2010/05/17)
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- Enantiomerically Pure P,N Chelates Based on Phospholene Rings: Palladium Complexes and Catalytic Applications in Allylic Substitution
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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
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experimental part
p. 5583 - 5591
(2010/06/15)
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- Modular furanoside phosphite-phosphoroamidites, a readily available ligand library for asymmetric palladium-catalyzed allylic substitution reactions. Origin of enantioselectivity
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A library of furanoside phosphite-phosphoroamidite ligands has been synthesized and screened in the palladium-catalyzed allylic substitution reactions of several substrate types. These series of ligands can be prepared efficiently from easily accessible D
- Raluy, Eva,Pamies, Oscar,Dieguez, Montserrat
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experimental part
p. 1648 - 1670
(2011/03/18)
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- P*,P*-Bidentate diastereoisomeric bisdiamidophosphites based on N-benzyltartarimide and their applications in asymmetric catalytic processes
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Two novel P*-stereogenic bisdiamidophosphites derived from (3R,4R)-N-benzyltartarimide as a chiral 1,2-diol have been prepared from readily available starting materials. Palladium and rhodium catalytic systems containing these new P*
- Gavrilov, Konstantin N.,Zheglov, Sergey V.,Benetsky, Eduard B.,Safronov, Anton S.,Rastorguev, Eugenie A.,Groshkin, Nikolay N.,Davankov, Vadim A.,Schaeffner, Benjamin,Boerner, Armin
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experimental part
p. 2490 - 2496
(2010/06/15)
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- Screening of a phosphite-phosphoramidite ligand library for palladium-catalysed asymmetric allylic substitution reactions: The origin of enantioselectivity
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We have designed a new library of readily available, highly modular phosphite-phosphoramidite ligands for asymmetric allylic substitution reactions. They are easily prepared in one step from commercially available chiral 1,2-amino alcohols. The introduction of a phosphoramidite moiety into the ligand design is highly advantageous for the product outcome. This ligand library affords high reaction rates (TOFs of up to 800 mol (mol h)-1) and enantioselectivities (ees of up to 99%) and, at the same time, contains a broad range of disubstituted hindered and unhindered substrate types. NMR study of the Pd-π-allyl intermediates provide a deeper understanding of the effect of the ligand parameters on the origin of cnantioselectivity.
- Pamies, Oscar,Dieguez, Montserrat
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p. 944 - 960
(2008/09/21)
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- Modular phosphite-oxazoline/oxazine ligand library for asymmetrie Pd-catalyzed allylic substitution reactions: scope and limitations - origin of enantioselectivity
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A library of phosphite-oxazoline/oxazine ligands L1-L15a-h has been synthesized and screened in the Pd-catalyzed allylic substitution reactions of several substrate types. These series of ligands can be prepared efficiently from easily accessible hydroxyl amino acid derivatives. Their modular nature enables the substituents/configurations in the oxazoline/oxazine moiety, alkyl backbone chain and in the biaryl phosphite moiety to be easily and systematically varied. By carefully selecting the ligand components, therefore, high regio- and enantioselectivities (ee values up to 99%) and good activities have been achieved in a broad range of mono- and disubstituted linear hindered and unhindered liner and cyclic substrates. The NMR studies on the Pd-π-allyl intermediates provide a deeper understanding about the effect of the ligand parameters on the origin of enantioselectivity. It also indicates that the nucleophilic attack takes place predominantly at the allylic terminal carbon atom located trans to the phosphite moiety.
- Dieguez, Montserrat,Pamies, Oscar
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experimental part
p. 3653 - 3669
(2009/04/23)
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- Exploring structural diversity in ligand design: The aminoindanol case
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A series of enantiopure ligands based on the aminoindanol scaffold, but differing in regio-and stereochemistry has been synthesized. These ligands have been conveniently derivatized and their catalytic efficiency in different enantioselective reactions has been screened to determine privileged candidates with respect to regio- and stereochemistry for each considered process. The nature of the amino substituent has been optimized for specific applications and this has led to the development of an efficient method for the preparation of bulky bicyclic amines by reductive amination.
- Rodriguez-Escrich, Sergi,Sola, Lluis,Jimeno, Ciril,Rodriguez-Escrich, Carles,Pericas, Miquel A.
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supporting information; experimental part
p. 2250 - 2260
(2009/10/06)
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- First chiral phosphoroamidite-phosphite ligands for highly enantioselective and versatile Pd-catalyzed asymmetric allylic substitution reactions
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(Chemical Equation Presented) A series of phosphite-phosphoroamidite ligands, derived from readily available D-xylose, has been successfully applied for the first time in the Pd-catalyzed allylic substitution of several substrates with different steric and electronic properties, with high enantioselectivities (ee's up to 98) and activities in standard conditions.
- Raluy, Eva,Claver, Carmen,Pamies, Oscar,Dieguez, Montserrat
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- Enantioselective glyoxylate-ene reaction using a novel spiro bis(isoxazoline) ligand in copper catalysis
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Novel chiral spiro bis(isoxazoline) ligands 3 and 4 are synthesized from an optically active olefin. The Cu(II)-spiro bis(isoxazoline) complex prepared in situ from Cu(OTf)2 and 3 promoted the glyoxylate-ene reaction in high yield and moderate
- Wakita, Kazuhiko,Bajracharya, Gan B.,Arai, Midori A.,Takizawa, Shinobu,Suzuki, Takeyuki,Sasai, Hiroaki
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p. 372 - 376
(2007/10/03)
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- Sugar-based diphosphoroamidite as a promising new class of ligands in Pd-catalyzed asymmetric allylic alkylation reactions
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(Chemical Equation Presented) We have designed a new family of readily available modular diphosphoroamidite ligands from D-xylose for Pd-catalyzed asymmetric allylic alkylation reactions. This constitutes the first example of diphosphoroamidite ligands ap
- Raluy, Eva,Dieguez, Montserrat,Pamies, Oscar
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p. 2842 - 2850
(2008/02/01)
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- A highly stereoselective divergent synthesis of bicyclic models of photoreactive sesquiterpene lactones
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Sesquiterpene lactones are natural stereochemically pure compounds, which show a number of biological activities. In order to study the reactivity of sesquiterpene lactones in biological systems, we describe herein the asymmetric synthesis of a simple mod
- Fuchs, Sebastien,Berl, Valerie,Lepoittevin, Jean-Pierre
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p. 1145 - 1152
(2008/02/06)
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- Novel C2-symmetric planar chiral diphosphine ligands and their application in Pd-catalyzed asymmetric allylic substitutions
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(Chemical Equation Presented) Novel C2-symmetric diphosphine ligands possessing only the planar chirality of ruthenocene, 1,1′-bis(diphenylphosphino)-2,2′-disubstituted-ruthenocenes (4), were prepared. With this kind of ligands, excellent enant
- Liu, Delong,Xie, Fang,Zhang, Wanbin
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p. 6992 - 6997
(2008/02/11)
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- New highly effective phosphite-phosphoramidite ligands for palladium-catalysed asymmetric allylic alkylation reactions
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We have designed a new family of readily I available highly-modular phosphite-phosphoramidite ligands for asymmetric allylic aJkylation reactions. The introduction of a phosphoramidite moiety in the ligand design is highly advantageous in the product outcome. Thus, this ligand series affords high reaction rates and enantioselectivities and, at the same time, shows a broad scope for disubstituted hindered and unhindered substrate types.
- Pamies, Oscar,Dieguez, Montserrat,Claver, Carmen
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p. 836 - 840
(2008/03/28)
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