- Asymmetric heck-type reaction utilizing hypervalent alkenyliodonium salt
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Asymetric Heck-type reaction of 1-cyclohexenylphenyliodonium salt with 2,3-dihydrofuran was investigated for the first time. The optically active (up to 78% ee) coupling product was obtained in low to moderate yield. The potential and associated problems
- Kurihara,Sodeoka,Shibasaki
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- Synthesis, Application and Kinetic Studies of Chiral Phosphite-Oxazoline Palladium Complexes as Active and Selective Catalysts in Intermolecular Heck Reactions
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This study identifies new phosphite-oxazoline ligands that have been successfully applied in the palladium-catalyzed intermolecular asymmetric Heck reaction. The design of the new phosphite-oxazoline ligands derives from a previous successful generation of phosphine-oxazoline ligands, by replacing the phosphine group with several π-acceptor biaryl phosphite moieties. With these simple modifications, the new phosphite-based ligands, unlike previous phosphine-oxazoline, not only present a modular design with numerous potential phosphite groups available, but they are also air-stable solids, which can be made in the same number of synthetic steps as the phosphine analogues. The substitution of the phosphine by a biaryl phosphite group extended the range of substrates and triflates sources that can be coupled with regio-, enantioselectivities and activities comparable to the few best ones reported. In addition, the ligands that provided the best selectivities contained an isopropyl oxazoline moiety instead of the tert-butyl group found in the related phosphine-oxazoline ligands, which is made from a much more expensive precursor. In this paper we have also carried out kinetic studies and a Hammett plot analysis to determine the rate determining step of this system in the regime of interest. We suggest a likely explanation for the fast Heck reaction of the phosphite-oxazoline catalysts. (Figure presented.).
- Mazloomi, Zahra,Magre, Marc,Del Valle, Efrem,Pericàs, Miquel A.,Pàmies, Oscar,van Leeuwen, Piet W. N. M.,Diéguez, Montserrat
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p. 1650 - 1664
(2018/03/21)
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- Phosphite-oxazole/imidazole ligands in asymmetric intermolecular Heck reaction
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We describe the application of a new class of ligands -the phosphite-oxazole/imidazole (L1-L5a-g) - in asymmetric intermolecular Pd-catalyzed Heck reactions under thermal and microwave conditions. These ligands combine the advantages of the oxazole/imidaz
- Mazuela, Javier,Tolstoy, Paivi,Pamies, Oscar,Andersson, Pher G.,Dieguez, Montserrat
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supporting information; experimental part
p. 941 - 946
(2011/03/22)
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- The synthesis of new HetPHOX ligands and their application to the intermolecular asymmetric heck reaction
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The synthesis of six members of the HetPHOX ligand class and the application of palladium complexes of these ligands to the intermolecular asymmetric Heck reaction is described, The tert-leucinol-derived ligands proved the most enantioselective, with pall
- Fitzpatrick, Martin O.,Muller-Bunz, Helge,Guiry, Patrick J.
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experimental part
p. 1889 - 1895
(2009/09/05)
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- Screening of a modular sugar-based phosphite-oxazoline ligand library in asymmetric Pd-catalyzed Heck reactions
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We have synthesised a library of phosphite-oxazoline ligands derived from readily available D-glucosamine. These ligands have been successfully screened in the palladium-catalysed Heck reaction of several substrates with high regio- (up to 99%) and enanti
- Mata, Yvette,Pàmies, Oscar,Diéguez, Montserrat
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p. 3296 - 3304
(2008/01/06)
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- Microwave-assisted asymmetric intermolecular heck reaction using phosphine-thiazole ligands
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A series of new phosphine-thiazole compounds has been synthesized and used as efficient ligands in the palladium-catalyzed asymmetric intermolecular Heck coupling of 2,3-dihydrofuran with aryl triflates and cyclohexenyl triflate. Microwave heating was used to accelerate the reactions and gave complete conversions in as little as one hour. Products were obtained with good to excellent enantioselectivities.
- Kaukoranta, Paeivi,Kaellstroem, Klas,Andersson, Pher G.
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p. 2595 - 2602
(2008/09/19)
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- Chiral phosphite-oxazolines: A new class of ligands for asymmetric Heck reactions
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(Chemical Equation Presented) A series of phosphite-oxazoline ligands, derived from readily available D-glucosamine, have been used for the first time in the palladium-catalyzed Heck reaction of several substrates with high regio- and enantioselectivities (ee's up to 99%) and improved activities in standard conditions.
- Mata, Yvette,Dieguez, Montserrat,Pamies, Oscar,Claver, Carmen
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p. 5597 - 5599
(2007/10/03)
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- The Application of HETPHOX Ligands to the Asymmetric Intermolecular Heck Reaction
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Two new heterocyclic diphenylphosphinooxazolines derived from thiophene and benzothiophene were prepared in moderate to good yield and these, and a range of related HETPHOX ligands, were applied in the intermolecular asymmetric Heck reaction. Phenylation of 2,3-dihydrofuran with the t-butyl-substituted thiophene-oxazoline ligand gave (R)-2-phenyl-2,3-dihydrofuran highly regioselectively with excellent enantioselectivity (91-95% ee) and in good yields (70-97%). In addition, cyclohexenylation of 2,3-dihydrofuran proceeded with enantioselectivities of up to 97% ee in excellent (97%) yields, again with the t-butyl-substituted thiophene-oxazoline ligand proving optimal over a range of reaction conditions investigated.
- Kilroy, Tim G.,Cozzi, Pier Giorgio,End, Nicole,Guiry, Patrick J.
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p. 106 - 110
(2007/10/03)
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- The application of Hetphox ligands to the asymmetric intermolecular heck reaction of 2,3-dihydrofuran and 2,2-disubstituted-2,3-dihydrofurans
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A series of thiophene- and benzothiophene-oxazoline containing ligands, were applied in the intermolecular asymmetric phenylation and cyclohexenylation of 2,3-dihydrofuran 1. Phenylation proceeded in moderate to high chemical yields, with good regioselectivities and in up to 95% ee. Cyclohexenylations gave similarly high chemical yields and regioselectivities with the optimal result being a 96% yield of the major product in 97% ee. 2,2-Dialkyl-2,3- dihydrofurans were also tested as substrates and the phenylation and cyclohexenylation of 2,2-dimethyl-2,3-dihydrofuran proceeded in high yields and ee's up to 91% and 89%, respectively. The phenylation and cyclohexenylation of the 2,2-diethyl analogue proceeded in excellent yields and ee's up to 99% and 87%, respectively. For each substrate, palladium complexes formed from the t-butyl-substituted ligand 10 gave the highest yields, regioselectivities, and enantioselectivities over the broad range of reaction conditions studied. 2,2-Diisopropyl-2,3-dihydrofuran was prepared but was found to be unreactive in the intermolecular Heck reaction thus providing insight into to the steric limits for 2,3-dihydrofuran substrates.
- Kilroy, Tim G.,Cozzi, Pier Giorgio,End, Nicole,Guiry, Patrick J.
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p. 1879 - 1888
(2007/10/03)
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- The regioselectivity of the asymmetric intermolecular Heck reaction with planar chiral diphosphine-oxazoline ferrocenyl ligands
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A series of novel planar chiral diphosphine-oxazoline ferrocenyl ligands were synthesized and used efficiently in the palladium-catalyzed asymmetric intermolecular Heck reaction of 2,3-dihydrofuran with aryl triflate and cyclohexenyl triflate. The tuning of the regioselectivity was realized by means of different palladium precursors and by changing the electronic factor of the ligands. A plausible rationale based on the existed mechanism is provided.
- Tu, Tao,Deng, Wei-Ping,Hou, Xue-Long,Dai, Li-Xin,Dong, Xi-Cheng
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p. 3073 - 3081
(2007/10/03)
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- Chiral bidentate (phosphinophenyl)benzoxazine ligands in asymmetric catalysis
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The new chiral bidentate (phosphinoaryl)benzoxazine ligands 2 were applied in asymmetric catalysis, Rhodium and copper complexes catalyzed the hydrosilylation of acetophenone and [4 + 2] cycloadditions with moderate enantioselectivity. Iridium complexes were used to hyrogenate di-, tri-, and tetrasubstituted alkenes, giving products with moderate to high enantiomer excesses. Enantioselective allylic substitution and Heck reactions catalyzed by [(phosphinoaryl)benzoxazine]palladium complexes occurred with high enantioselectivities. The results were similar to those obtained with the corresponding dihydro(phosphinoaryl)oxazole ligands. Comparison of the structures of (diphenylallyl)(benzoxazine)palladium and (diphenylallyl)(dihydrooxazole)-palladium complexes showed that the coordination geometries and the chiral environments of the metal centers are very similar, which explains why the enantioselectivities induced by the two ligand classes are in the same range.
- Bernardinelli, Gerald H.,Kuendig, E. Peter,Meier, Peter,Pfaltz, Andreas,Radkowski, Karin,Zimmermann, Nicole,Neuburger-Zehnder, Margareta
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p. 3233 - 3246
(2007/10/03)
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- Proline derived phosphine-oxazoline ligands in the asymmetric Heck reaction
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A phosphine-oxazoline ligand system based on hydroxyproline is used as an asymmetric ligand for palladium. Complexes of this type are reported as catalysts for the asymmetric Heck reaction.
- Gilbertson, Scott R.,Fu, Zice,Xie, Dejian
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p. 365 - 368
(2007/10/03)
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- Chiral P,N-ligands based on ketopinic acid in the asymmetric heck reaction
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equation presented Novel chiral P,N-ligands were synthesized from (1S)-(+)-ketopinic acid using palladium-catalyzed coupling reaction of a vinyl triflate and either a diarylphosphine or a dialkylphosphine as the key step. Palladium complexes of these ligands are efficient catalysts for asymmetric Heck reaction between aryl or alkenyl triflates and cyclic alkenes. Products were obtained with good to excellent enantioselectivity from arylation and alkenylation of 1,2-dihydrofuran, cyclopentene, and 4,7-dihydro-1,3-dioxepin.
- Gilbertson, Scott R.,Fu, Zice
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p. 161 - 164
(2007/10/03)
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- An efficient phosphorus-containing oxazoline ligand derived from cis-2-amino-3,3-dimethyl-1-indanol: Application to the palladium-catalyzed asymmetric Heck reaction
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Enantiopure 2-[2-(diphenylphosphino)phenyl]oxazoline, derived from a non-natural chiral aminoalcohol, cis-2-amino-3,3-dimethyl-1-indanol, was found to be an efficient ligand for the palladium-catalyzed asymmetric Heck reaction. Copyright (C) 2000 Elsevier
- Hashimoto, Yukihiko,Horie, Yumi,Hayashi, Minoru,Saigo, Kazuhiko
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p. 2205 - 2210
(2007/10/03)
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- Enantioselective heck reactions catalyzed by chiral phosphinooxazoline-palladium complexes
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Palladium complexes with chiral phosphinooxazoline ligands are efficient catalysts for enantioselective Heck reactions with aryl or alkenyl triflates and cyclic alkenes. In the arylation and alkenylation of 1,2-dihydrofuran, cyclopentene, 2,3-dihydro-4H-p
- Loiseleur,Hayashi,Schmees,Pfaltz
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p. 1338 - 1345
(2007/10/03)
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- Chirale Phosphanyldihydrooxazole in der asymmetrischen Katalyse: enantioselektive Heck-Reaktionen
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Keywords: Asymmetrische Katalyse; Dihydrooxazole; Heck-Reaktionen; Pd-Katalysatoren; P,N-Liganden
- Loiseleur, Olivier,Meier, Peter,Pfaltz, Andreas
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p. 218 - 220
(2007/10/03)
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