1401
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Hong AY, Krout MR, Jensen T, Bennett NB, Harned AM, Stoltz BM. Ring-contraction strategy for the practical, scalable, catalytic asymmetric synthesis of versatile γ-quaternary acylcyclopentenes. Angew Chem Int Ed Engl 2011; 50:2756-60. [PMID: 21387482 PMCID: PMC3365661 DOI: 10.1002/anie.201007814] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2010] [Indexed: 11/07/2022]
Abstract
A simple protocol for the practical, scalable, catalytic asymmetric synthesis of γ-quaternary acylcyclopentenes in up to 91% overall yield and 92% ee has been developed. The reaction sequence employs a palladium-catalyzed enantioselective alkylation reaction and exploits the unusual stability of β-hydroxy cycloheptanones to achieve a general and robust method for performing two-carbon ring contractions. The resulting enantioenriched, highly-functionalized acylcyclopentenes provide a variable substituent and four additional functional group handles for chemoselective manipulation and potential application to the total synthesis of a wide array of natural products.
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Affiliation(s)
- Allen Y. Hong
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering Division of Chemistry and Chemical Engineering California Institute of Technology, 1200 E. California Blvd, MC 101-20, Pasadena, CA 91125 (USA), Fax: (+1) 626-395-8436
| | - Michael R. Krout
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering Division of Chemistry and Chemical Engineering California Institute of Technology, 1200 E. California Blvd, MC 101-20, Pasadena, CA 91125 (USA), Fax: (+1) 626-395-8436
| | - Thomas Jensen
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering Division of Chemistry and Chemical Engineering California Institute of Technology, 1200 E. California Blvd, MC 101-20, Pasadena, CA 91125 (USA), Fax: (+1) 626-395-8436
| | - Nathan B. Bennett
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering Division of Chemistry and Chemical Engineering California Institute of Technology, 1200 E. California Blvd, MC 101-20, Pasadena, CA 91125 (USA), Fax: (+1) 626-395-8436
| | - Andrew M. Harned
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering Division of Chemistry and Chemical Engineering California Institute of Technology, 1200 E. California Blvd, MC 101-20, Pasadena, CA 91125 (USA), Fax: (+1) 626-395-8436
| | - Brian M. Stoltz
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering Division of Chemistry and Chemical Engineering California Institute of Technology, 1200 E. California Blvd, MC 101-20, Pasadena, CA 91125 (USA), Fax: (+1) 626-395-8436
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1402
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Rios IG, Rosas-Hernandez A, Martin E. Recent advances in the application of chiral phosphine ligands in Pd-catalysed asymmetric allylic alkylation. Molecules 2011; 16:970-1010. [PMID: 21258301 PMCID: PMC6264407 DOI: 10.3390/molecules16010970] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 12/02/2022] Open
Abstract
One of the most powerful approaches for the formation of simple and complex chiral molecules is the metal-catalysed asymmetric allylic alkylation. This reaction has been broadly studied with a great variety of substrates and nucleophiles under different reaction conditions and it has promoted the synthesis of new chiral ligands to be evaluated as asymmetric inductors. Although the mechanism as well as the active species equilibria are known, the performance of the catalytic system depends on the fine tuning of factors such as type of substrate, nucleophile nature, reaction medium, catalytic precursor and type of ligand used. Particularly interesting are chiral phosphines which have proved to be effective asymmetric inductors in several such reactions. The present review covers the application of phosphine-donor ligands in Pd-catalysed asymmetric allylic alkylation in the last decade.
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Affiliation(s)
| | | | - Erika Martin
- Departamento de Química Inorgánica, Facultad de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, 04510 México D.F., Mexico
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1403
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Fischer C, Koenig B. Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds. Beilstein J Org Chem 2011; 7:59-74. [PMID: 21286396 PMCID: PMC3029007 DOI: 10.3762/bjoc.7.10] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 12/14/2010] [Indexed: 11/23/2022] Open
Abstract
N-Arylated aliphatic and aromatic amines are important substituents in many biologically active compounds. In the last few years, transition-metal-mediated N-aryl bond formation has become a standard procedure for the introduction of amines into aromatic systems. While N-arylation of simple aromatic halides by simple amines works with many of the described methods in high yield, the reactions may require detailed optimization if applied to the synthesis of complex molecules with additional functional groups, such as natural products or drugs. We discuss and compare in this review the three main N-arylation methods in their application to the synthesis of biologically active compounds: Palladium-catalysed Buchwald-Hartwig-type reactions, copper-mediated Ullmann-type and Chan-Lam-type N-arylation reactions. The discussed examples show that palladium-catalysed reactions are favoured for large-scale applications and tolerate sterically demanding substituents on the coupling partners better than Chan-Lam reactions. Chan-Lam N-arylations are particularly mild and do not require additional ligands, which facilitates the work-up. However, reaction times can be very long. Ullmann- and Buchwald-Hartwig-type methods have been used in intramolecular reactions, giving access to complex ring structures. All three N-arylation methods have specific advantages and disadvantages that should be considered when selecting the reaction conditions for a desired C-N bond formation in the course of a total synthesis or drug synthesis.
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Affiliation(s)
- Carolin Fischer
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Burkhard Koenig
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
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1404
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Abstract
Several 2-iodopyrroles are used in Pd(0) catalyzed homocoupling reactions at room temperature in the presence of water to efficiently synthesize 2,2'-bipyrroles. These 2,2'-bipyrroles are strongly luminous materials and have high fluorescence quantum yields.
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Affiliation(s)
- Lijuan Jiao
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
- Anhui Key Laboratory of Functional Molecular Solids and Anhui Key Laboratory of Molecular Based Materials College of Chemistry and Material Science, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Erhong Hao
- Anhui Key Laboratory of Functional Molecular Solids and Anhui Key Laboratory of Molecular Based Materials College of Chemistry and Material Science, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | - M. Graça H. Vicente
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Kevin M. Smith
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
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1405
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Izawa Y, Stahl SS. Aerobic Oxidative Coupling of o-Xylene: Discovery of 2-Fluoropyridine as a Ligand to Support Selective Pd-Catalyzed C-H Functionalization. Adv Synth Catal 2010; 352:3223-3229. [PMID: 21399704 PMCID: PMC3049937 DOI: 10.1002/adsc.201000771] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
An improved method for direct oxidative coupling of o-xylene could provide streamlined access to an important monomer used in polyimide resins. The use of 2-fluoropyridine as a ligand has been found to enable unprecedented levels of chemo- and regioselectivity in this Pd-catalyzed aerobic oxidative coupling reaction. Preliminary insights have been obtained into the origin of the effectiveness of 2-fluoropyridine as a ligand.
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Affiliation(s)
- Yusuke Izawa
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA. Fax: (+1) 608-262-6143;
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA. Fax: (+1) 608-262-6143;
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1406
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Chernyak N, Tilly D, Li Z, Gevorgyan V. Cascade carbopalladation-annulation approach toward polycylic derivatives of indole and indolizine. ARKIVOC 2010; 2011:76-91. [PMID: 24498633 PMCID: PMC3909657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023] Open
Abstract
A convenient method for construction of polycyclic fused nitrogen-containing heterocycles has been developed. The methodology involves palladium-catalyzed intermolecular carbopalladation-annulation cascade reaction of haloaryl heterocyclic derivatives with different alkynes under relatively mild reaction conditions. Thus, the palladium-catalyzed cascade cyclization of bromophenyl derivatives of indolizine and indole with alkynes afforded tetracycles, possessing a newly formed fused six-membered ring. The reaction of 3-(2-iodobenzyl)-indoles with a variety of alkynes afforded polycyclic compounds with fused seven-membered rings. Annulation with unsymmetrical alkynes exhibited varied regioselectivity. Overall, this approach allows for quick and efficient assembly of polycyclic derivatives of indole and indolizine from easily available precursors.
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Affiliation(s)
- Natalia Chernyak
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, United States
| | - David Tilly
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, United States
| | - Zhou Li
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, United States
| | - Vladimir Gevorgyan
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, United States
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1407
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Abstract
Palladium-catalyzed C-H activation/C-C bond-forming reactions have emerged as a promising class of synthetic tools in organic chemistry. Among the many different means of forging C-C bonds using Pd-mediated C-H activation, a new horizon in this field is Pd(II)-catalyzed cross-coupling of C-H bonds with organometallic reagents via a Pd(II)/Pd(0) catalytic cycle. While this type of reaction has proven to be effective for the selective functionalization of aryl C(sp(2))-H bonds, the focus of this review is on Pd(II)-catalyzed C(sp(3))-H activation/C-C cross-coupling, a topic of particular importance because reactions of this type enable fundamentally new methods for bond construction. Since our laboratory's initial report on cross-coupling of C-H bonds in 2006, this area has expanded rapidly, and the unique ability of Pd(II) catalysts to cleave and functionalize alkyl C(sp(3))-H bonds has been exploited to develop protocols for forming an array of C(sp(3))-C(sp(2)) and C(sp(3))-C(sp(3)) bonds. Furthermore, enantioselective C(sp(3))-H activation/C-C cross-coupling has been achieved through the use of chiral amino acid-derived ligands, offering a novel technique for producing enantioenriched molecules. Although this nascent field remains at an early stage of development, further investigations hold the potential to revolutionalize the way in which chiral molecules are synthesized in industrial and academic laboratories.
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Affiliation(s)
- Masayuki Wasa
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037 (USA)
| | - Keary M. Engle
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037 (USA)
| | - Jin-Quan Yu
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037 (USA)
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1408
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Dudnik AS, Chernyak N, Huang C, Gevorgyan V. A general strategy toward aromatic 1,2-ambiphilic synthons: palladium-catalyzed ortho-halogenation of PyDipSi-arenes. Angew Chem Int Ed Engl 2010; 49:8729-32. [PMID: 20886495 PMCID: PMC3132816 DOI: 10.1002/anie.201004426] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Alexander S. Dudnik
- Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St, Rm 4500, Chicago, IL 60607 (USA), Fax: (+1)312-355-0836
| | - Natalia Chernyak
- Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St, Rm 4500, Chicago, IL 60607 (USA), Fax: (+1)312-355-0836
| | - Chunhui Huang
- Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St, Rm 4500, Chicago, IL 60607 (USA), Fax: (+1)312-355-0836
| | - Vladimir Gevorgyan
- Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St, Rm 4500, Chicago, IL 60607 (USA), Fax: (+1)312-355-0836
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1409
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Abstract
Pd(2)(dba)(3)/[HP(t-Bu)(3)]BF(4)/KF•2H(2)O serves as a mild, robust, and user-friendly method for the efficient Suzuki cross-coupling of a diverse array of aryl and heteroaryl halides with aryl- and heteroarylboronic acids.
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Affiliation(s)
- Sha Lou
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Gregory C. Fu
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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1410
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Adeloye AO, Ajibade PA. Synthesis and characterization of a heteroleptic Ru(II) complex of phenanthroline containing oligo-anthracenyl carboxylic acid moieties. Int J Mol Sci 2010; 11:3158-76. [PMID: 20957086 PMCID: PMC2956087 DOI: 10.3390/ijms11093158] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 08/12/2010] [Accepted: 08/12/2010] [Indexed: 11/16/2022] Open
Abstract
In an effort to develop new ruthenium(II) complexes, this work describes the design, synthesis and characterization of a ruthenium(II) functionalized phenanthroline complex with extended π-conjugation. The ligand were L(1) (4,7-bis(2,3-dimethylacrylic acid)-1,10-phenanthroline), synthesized by a direct aromatic substitution reaction, and L(2) (4,7-bis(trianthracenyl-2,3-dimethylacrylic acid)-1,10-phenanthroline), which was synthesized by the dehalogenation of halogenated aromatic compounds using a zero-valent palladium cross-catalyzed reaction in the absence of magnesium-diene complexes and/or cyclooctadienyl nickel (0) catalysts to generate a new carbon-carbon bond (C-C bond) polymerized hydrocarbon units. The ruthenium complex [RuL(1)L(2)(NCS)(2)] showed improved photophysical properties (red-shifted metal-to-ligand charge-transfer transition absorptions and enhanced molar extinction coefficients), luminescence and interesting electrochemical properties. Cyclic and square wave voltammetry revealed five major redox processes. The number of electron(s) transferred by the ruthenium complex was determined by chronocoulometry in each case. The results show that processes I, II and III are multi-electron transfer reactions while processes IV and V involved one-electron transfer reaction. The photophysical property of the complex makes it a promising candidate in the design of chemosensors and photosensitizers, while its redox-active nature makes the complex a potential mediator of electron transfer in photochemical processes.
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Affiliation(s)
- Adewale O Adeloye
- Department of Chemistry, Faculty of Science and Agriculture, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa; E-Mail:
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1411
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Affiliation(s)
| | - John F Hartwig
- Department of Chemistry, University of Illinois Urbana-Champaign Urbana, Il 61801 (USA) Fax: (+ 1) 217-244-8024 Homepage: http://www.scs.uiuc.edu/hartwig/
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1412
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Abstract
Allylic sulfamides undergo efficient aerobic oxidative cyclization at room temperature, mediated by a new Pd catalyst system consisting of 5% Pd(TFA)2/10% DMSO in THF. The synthetic utility of these reactions is enhanced by several features: (1) the sulfamide substrates are accessible in multi-gram scale from the corresponding allylic and primary amines, (2) the cyclic sulfamide products are readily converted to the corresponding 1,2-diamines upon treatment with LiAlH4, and (3) substrates derived from chiral allylic amines cyclize with very high levels of diastereoselectivity.
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Affiliation(s)
- Richard I. McDonald
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706 (USA), Fax: (+1) 608-262-6143
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706 (USA), Fax: (+1) 608-262-6143
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1413
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McDonald RI, Stahl SS. Modular Synthesis of 1,2-Diamine Derivatives via Palladium-Catalyzed Aerobic Oxidative Cyclization of Allylic Sulfamides. Angew Chem Int Ed Engl 2010; 122:5661-5664. [PMID: 21132102 PMCID: PMC2996102 DOI: 10.1002/ange.200906342] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Allylic sulfamides undergo efficient aerobic oxidative cyclization at room temperature, mediated by a new Pd catalyst system consisting of 5% Pd(TFA)(2)/10% DMSO in THF. The synthetic utility of these reactions is enhanced by several features: (1) the sulfamide substrates are accessible in multi-gram scale from the corresponding allylic and primary amines, (2) the cyclic sulfamide products are readily converted to the corresponding 1,2-diamines upon treatment with LiAlH(4), and (3) substrates derived from chiral allylic amines cyclize with very high levels of diastereoselectivity.
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Affiliation(s)
- Richard I. McDonald
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706 (USA), Fax: (+1) 608-262-6143, Homepage: http://www.chem.wisc.edu/~stahl
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706 (USA), Fax: (+1) 608-262-6143, Homepage: http://www.chem.wisc.edu/~stahl
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1414
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McGrew GI, Temaismithi J, Carroll PJ, Walsh PJ. Synthesis of polyarylated methanes through cross-coupling of tricarbonylchromium-activated benzyllithiums. Angew Chem Int Ed Engl 2010; 49:5541-4. [PMID: 20602381 PMCID: PMC3409573 DOI: 10.1002/anie.201000957] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Genette I. McGrew
- UPenn/Merck HTE Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34 St, Philadelphia, Pennsylvania, 19104, USA, Fax: (+) 1 215 573 6743, Homepage: http://titanium.chem.upenn.edu/walsh/index.html
| | - Jesada Temaismithi
- UPenn/Merck HTE Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34 St, Philadelphia, Pennsylvania, 19104, USA, Fax: (+) 1 215 573 6743, Homepage: http://titanium.chem.upenn.edu/walsh/index.html
| | - Patrick J. Carroll
- UPenn/Merck HTE Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34 St, Philadelphia, Pennsylvania, 19104, USA, Fax: (+) 1 215 573 6743, Homepage: http://titanium.chem.upenn.edu/walsh/index.html
| | - Patrick J. Walsh
- UPenn/Merck HTE Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34 St, Philadelphia, Pennsylvania, 19104, USA, Fax: (+) 1 215 573 6743, Homepage: http://titanium.chem.upenn.edu/walsh/index.html
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1415
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Astruc D, Ornelas C, Diallo AK, Ruiz J. Extremely efficient catalysis of carbon-carbon bond formation using "click" dendrimer-stabilized palladium nanoparticles. Molecules 2010; 15:4947-60. [PMID: 20657402 PMCID: PMC6257605 DOI: 10.3390/molecules15074947] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 07/08/2010] [Accepted: 07/12/2010] [Indexed: 11/16/2022] Open
Abstract
This article is an account of the work carried out in the authors' laboratory illustrating the usefulness of dendrimer design for nanoparticle palladium catalysis. The "click" synthesis of dendrimers constructed generation by generation by 1-->3 C connectivity, introduces 1,2,3-triazolyl ligands insides the dendrimers at each generation. Complexation of the ligands by Pd(II) followed by reduction to Pd(0) forms dendrimer-stabilized Pd nanoparticles (PdNPs) that are extremely reactive in the catalysis of olefin hydrogenation and C-C bond coupling reactions. The stabilization can be outer-dendritic for the small zeroth-generation dendrimer or intra-dendritic for the larger first- and second-generation dendrimers. The example of the Miyaura-Suzuki reaction that can be catalyzed by down to 1 ppm of PdNPs with a "homeopathic" mechanism (the less, the better) is illustrated here, including catalysis in aqueous solvents.
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Affiliation(s)
- Didier Astruc
- ISM, UMR CNRS N degrees 5255, Université Bordeaux 1, 3305 Talence Cedex, France.
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1416
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Abstract
Protocols to effect β-arylation of sp(3) C-H bonds via Pd(II)/(IV) and Pd(0)/(II) catalytic cycles have been achieved using a newly developed monodentate CONHC(6)F(5) directing group. These reactions provide an unprecedented means to functionalize sp(3) C-H bonds in aliphatic carboxylic acid-derived substrates.
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Affiliation(s)
- Masayuki Wasa
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jin-Quan Yu
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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1417
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Monopoli A, Nacci A, Calò V, Ciminale F, Cotugno P, Mangone A, Giannossa LC, Azzone P, Cioffi N. Palladium/zirconium oxide nanocomposite as a highly recyclable catalyst for C-C coupling reactions in water. Molecules 2010; 15:4511-25. [PMID: 20657374 PMCID: PMC6257561 DOI: 10.3390/molecules15074511] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 06/16/2010] [Accepted: 06/21/2010] [Indexed: 11/25/2022] Open
Abstract
Palladium nanoparticles have been electrochemically supported on zirconium oxide nanostructured powders and all the nanomaterials have been characterized by several analytical techniques. The Pd/ZrO(2) nanocatalyst is demonstrated to be a very efficient catalyst in Heck, Ullmann, and Suzuki reactions of aryl halides in water. The catalyst efficiency is attributed to the stabilization of Pd nanophases provided by tetra(alkyl)- ammonium hydroxide, which behaves both as base and PTC (phase transfer catalyst) agent.
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Affiliation(s)
- Antonio Monopoli
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
| | - Angelo Nacci
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
- CNR – ICCOM, Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
| | - Vincenzo Calò
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
| | - Francesco Ciminale
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
| | - Pietro Cotugno
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
| | - Annarosa Mangone
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
| | - Lorena Carla Giannossa
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
| | - Pietro Azzone
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
| | - Nicola Cioffi
- Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126-Bari, Italy
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1418
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Abstract
This article describes the development of a Pd-catalyzed reaction for the arylhalogenation (halogen = Cl or Br) of diverse alpha-olefins by oxidatively intercepting Mizoroki-Heck intermediates. These transformations afford synthetically useful 1,2- and 1,1-arylhalogenated products in good yields with good to excellent selectivities that can be modulated by changing the nature of the halogenating reagent and/or the reaction conditions. The selectivity of these reactions can be rationally tuned by (i) controlling the relative rates of oxidative functionalization versus beta-hydride elimination from equilibrating Pd(II)-alkyl species and (ii) stabilization of organometallic Pd(II) intermediates through the formation of pi-benzyl adducts. These arylhalogenations exhibit modest to excellent levels of stereoselectivity, and the key carbon-halogen bond-forming step proceeds with predominant retention of stereochemistry at carbon.
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Affiliation(s)
- Dipannita Kalyani
- University of Michigan, Department of Chemistry, 930 North University Ave, Ann Arbor, MI 48109
| | - Andrew D. Satterfield
- University of Michigan, Department of Chemistry, 930 North University Ave, Ann Arbor, MI 48109
| | - Melanie S. Sanford
- University of Michigan, Department of Chemistry, 930 North University Ave, Ann Arbor, MI 48109
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1419
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Abstract
A selection of carbon-fluorine bond-forming reactions is presented with particular focus on transition metal-mediated fluorination. A brief summary of conventional fluorination reactions is followed by a discussion of fluorination reactions mediated by palladium and silver. Investigations into the mechanism as well as the conceptual difficulty associated with transition metal-mediated carbon-fluorine bond formation are presented.
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Affiliation(s)
- Takeru Furuya
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, Fax: +1(617)4964591
| | - Johannes E. M. N. Klein
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, Fax: +1(617)4964591
| | - Tobias Ritter
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, Fax: +1(617)4964591
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1420
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Gooßen LJ, Zimmermann B, Knauber T. Pd-catalyzed decarboxylative Heck vinylation of 2-nitrobenzoates in the presence of CuF₂. Beilstein J Org Chem 2010; 6:43. [PMID: 20563276 PMCID: PMC2887305 DOI: 10.3762/bjoc.6.43] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 04/10/2010] [Indexed: 11/23/2022] Open
Abstract
A new protocol for the decarboxylative Heck vinylation of benzoic acids is disclosed. In the presence of a catalyst system generated in situ from Pd(OAc)2 (2 mol %), CuF2 (2 equiv), and benzoquinone (0.5 equiv) in NMP, a wide range of olefins were coupled with various 2-nitrobenzoates at 130 °C with the release of carbon dioxide to afford the corresponding vinyl arenes in good yields.
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Affiliation(s)
- Lukas J Gooßen
- Department of Chemistry, Organic Chemistry, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse, Geb. 54, D-67663 Kaiserslautern, Germany.
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1421
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Deagostino A, Prandi C, Tabasso S, Venturello P. The Heck reaction applied to 1,3- and 1,2-unsaturated derivatives, a way towards molecular complexity. Molecules 2010; 15:2667-85. [PMID: 20428072 PMCID: PMC6257322 DOI: 10.3390/molecules15042667] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 03/26/2010] [Accepted: 04/01/2010] [Indexed: 12/04/2022] Open
Abstract
This review is an overview of the last ten years' use of the Mizoroki-Heck coupling applied to 1,2- and 1,3-dienes. Since both these systems form pi-allyl palladium intermediates in Pd(0) coupling, they show particular chemical behavior. Many examples of 1,2-dienes Heck reactions are presented. 1,2-Dienes are important substrates because of their high reactivity that makes them useful building blocks for the synthesis of biologically relevant structures.
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Affiliation(s)
- Annamaria Deagostino
- Dipartimento di Chimica Generale e Chimica Organica, Università di Torino, Via Pietro Giuria, Torino, Italy.
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1422
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Abstract
Our program, which has focused on the preparation of new pyrazole derivatives, has led us to report here an original and simplified preparation of ethyl 3-ethoxy-1H-pyrazole-4-carboxylate. This is based on the reaction of hydrazine monohydrochloride and diethyl 2-(ethoxymethylene)malonate. Further transformations of this key compound allowed the preparation of the two possible iodinated isomers, namely, 3-ethoxy-4-iodo- and 3-ethoxy-5-iodo-1H-pyrazole. These compounds have opened the way to a quick access to many original pyrazole series. As an illustration, we report here on the selectivity of N-arylation, by using the Lam and Cham method, the C4- and C5-arylation of some of these 3-ethoxypyrazole derivatives by using the Suzuki-Miyaura reaction, and C5-benzylation reactions by means of the Negishi reaction. This was followed by hydrolysis of the ethoxy group, which led to the corresponding pyrazol-3-one derivatives. As a conclusion of this work, we conducted an investigation into the regiochemistry of the condensation between diethyl 2-(ethoxymethylene)malonate and the hydrochloride salts of methyl, benzyl, or phenyl hydrazine.
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Affiliation(s)
- Sandrine Guillou
- Institut Pasteur, URA 2128 CNRS-Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris cedex 15 (France), Fax: (+33) 145688404
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1423
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Abstract
At the palladium: Dimeric palladium bromide complexes bearing monodentate N-heterocyclic carbene ligands have been identified as efficient catalysts for the chemoselective racemization of axially chiral allenyl alcohols. In combination with porcine pancreatic lipase as biocatalyst, a dynamic kinetic resolution has been developed, giving access to optically active allenes in good yield and high enantiomeric purity (see scheme).
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Affiliation(s)
- Jan Deska
- Department of Organic Chemistry, Arrheniuslaboratoriet, Stockholm University, S-10691 Stockholm (Sweden), Fax: (+46) 8-154908
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1424
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El Gowini MM, Moussa WA. A finite element model of a MEMS-based surface acoustic wave hydrogen sensor. Sensors (Basel) 2010; 10:1232-50. [PMID: 22205865 DOI: 10.3390/s100201232] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 12/31/2009] [Accepted: 01/23/2010] [Indexed: 11/18/2022]
Abstract
Hydrogen plays a significant role in various industrial applications, but careful handling and continuous monitoring are crucial since it is explosive when mixed with air. Surface Acoustic Wave (SAW) sensors provide desirable characteristics for hydrogen detection due to their small size, low fabrication cost, ease of integration and high sensitivity. In this paper a finite element model of a Surface Acoustic Wave sensor is developed using ANSYS12© and tested for hydrogen detection. The sensor consists of a YZ-lithium niobate substrate with interdigital electrodes (IDT) patterned on the surface. A thin palladium (Pd) film is added on the surface of the sensor due to its high affinity for hydrogen. With increased hydrogen absorption the palladium hydride structure undergoes a phase change due to the formation of the β-phase, which deteriorates the crystal structure. Therefore with increasing hydrogen concentration the stiffness and the density are significantly reduced. The values of the modulus of elasticity and the density at different hydrogen concentrations in palladium are utilized in the finite element model to determine the corresponding SAW sensor response. Results indicate that with increasing the hydrogen concentration the wave velocity decreases and the attenuation of the wave is reduced.
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1425
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Borisov SM, Zenkl G, Klimant I. Phosphorescent platinum(II) and palladium(II) complexes with azatetrabenzoporphyrins-new red laser diode-compatible indicators for optical oxygen sensing. ACS Appl Mater Interfaces 2010; 2:366-74. [PMID: 20186289 PMCID: PMC2828183 DOI: 10.1021/am900932z] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 01/21/2010] [Indexed: 05/27/2023]
Abstract
A new class of oxygen indicators is described. Platinum(II) and palladium(II) complexes of azatetrabenzoporphyrins occupy an intermediate position between tetrabenzoporphyrins and phthalocyanines and combine features of both. The new dyes are excitable in the red part of the spectrum and possess strong room-temperature NIR phosphorescence. Other features include excellent spectral compatibility with the red laser diodes and 632.8 nm line of He-Ne laser, excellent photostability, and significantly shorter decay times than for the respective meso-tetraphenyltetrabenzoporphyrins. Applicability of the complexes for optical oxygen sensing is demonstrated.
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Affiliation(s)
- Sergey M Borisov
- Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria.
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1426
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Bernhardt F, Trotzki R, Szuppa T, Stolle A, Ondruschka B. Solvent-free and time-efficient Suzuki-Miyaura reaction in a ball mill: the solid reagent system KF-Al(2)O(3) under inspection. Beilstein J Org Chem 2010; 6:7. [PMID: 20485589 PMCID: PMC2870998 DOI: 10.3762/bjoc.6.7] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 12/23/2009] [Indexed: 11/23/2022] Open
Abstract
Although a plethora of synthetic procedures mediated by KF-loaded aluminas is available in the literature, there is almost no data concerning the influence of parameters such as alumina modification or KF-loading on experimental results. Hence, the Pd-catalyzed, solvent-free Suzuki–Miyaura reaction was chosen as model reaction to investigate the effect of the above mentioned parameters on the results of coupling reactions. The results from ball milling experiments led to the conclusion that self-prepared and commercially available KF–Al2O3 differ in water content. The higher the residual water content, the higher are the product yields.
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Affiliation(s)
- Franziska Bernhardt
- Institute for Technical Chemistry and Environmental Chemistry, Friedrich-Schiller University Jena, Lessingstrasse 12, D-07743 Jena, Germany
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1427
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Affiliation(s)
- Takashi Nishikata
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, CA 93106 (USA)
| | - Alexander R. Abela
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, CA 93106 (USA)
| | - Bruce H. Lipshutz
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, CA 93106 (USA)
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1428
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McDougal NT, Virgil SC, Stoltz BM. High-Throughput Screening of the Asymmetric Decarboxylative Alkylation Reaction of Enolate-Stabilized Enol Carbonates. Synlett 2010; 11:1712-1716. [PMID: 21072327 PMCID: PMC2976558 DOI: 10.1055/s-0030-1258094] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing to a non-polar reaction solvent and to an electron-deficient PHOX derivative as ligand from our standard reaction conditions improved the enantioselectivity for the alkylation of a ketal-protected,1,3-diketone-derived enol carbonate from 28% ee to 84% ee. Similar improvements in enantioselectivity were seen for a β-keto-ester derived- and an α-phenyl cyclohexanone-derived enol carbonate.
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Affiliation(s)
- Nolan T. McDougal
- The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Scott C. Virgil
- The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Brian M. Stoltz
- The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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1429
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Ebner DC, Bagdanoff JT, Ferreira EM, McFadden RM, Caspi DD, Trend RM, Stoltz BM. The palladium-catalyzed aerobic kinetic resolution of secondary alcohols: reaction development, scope, and applications. Chemistry 2009; 15:12978-92. [PMID: 19904777 PMCID: PMC2862982 DOI: 10.1002/chem.200902172] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The first palladium-catalyzed enantioselective oxidation of secondary alcohols has been developed, utilizing the readily available diamine (-)-sparteine as a chiral ligand and molecular oxygen as the stoichiometric oxidant. Mechanistic insights regarding the role of the base and hydrogen-bond donors have resulted in several improvements to the original system. Namely, addition of cesium carbonate and tert-butyl alcohol greatly enhances reaction rates, promoting rapid resolutions. The use of chloroform as solvent allows the use of ambient air as the terminal oxidant at 23 degrees C, resulting in enhanced catalyst selectivity. These improved reaction conditions have permitted the successful kinetic resolution of benzylic, allylic, and cyclopropyl secondary alcohols to high enantiomeric excess with good-to-excellent selectivity factors. This catalyst system has also been applied to the desymmetrization of meso-diols, providing high yields of enantioenriched hydroxyketones.
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Affiliation(s)
| | | | | | | | | | | | - Brian M. Stoltz
- The Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., MC 164-30, Pasadena, CA 91125 (USA), Fax: (+1) 626-564-9297
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1430
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Olson AC, Overman LE, Sneddon HF, Ziller JW. Catalytic Asymmetric Synthesis of Branched Chiral Allylic Phenyl Ethers from ( E)-Allylic Alcohols. Adv Synth Catal 2009; 351:3186-3192. [PMID: 23795152 DOI: 10.1002/adsc.200900678] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The first di-μ-amidate dipalladium complexes and a new di-μ-carboxylate dipalladium complex of the COP (cobalt oxazoline palladacycle) palladium(II) catalyst family are reported and characterized crystallographically. The di-μ-amidate complex 3 or its enantiomer (ent-3) are the first asymmetric catalysts that allow commercially available, or readily accessible, (E)-2-alkene-1-ols to be transformed to enantioenriched branched allylic aryl ethers upon reaction of their trichloroacetimidate derivatives with phenols. The 3-aryloxy-1-alkene products are formed in high enantiomeric purity (typically 90-98% ee) and useful yields (61-88%).
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Affiliation(s)
- Angela C Olson
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California, 92697-2025, U.S.A
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1431
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Gorja DR, Batchu VR, Ettam A, Pal M. Pd/C-mediated synthesis of α-pyrone fused with a five-membered nitrogen heteroaryl ring: a new route to pyrano[4,3-c]pyrazol-4(1H)-ones. Beilstein J Org Chem 2009; 5:64. [PMID: 20300500 PMCID: PMC2839514 DOI: 10.3762/bjoc.5.64] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 10/22/2009] [Indexed: 11/23/2022] Open
Abstract
Pd/C-mediated alkynylation of 5-iodo-pyrazole-4-carboxylic acid, involving the first regioselective construction of α-pyrone ring on a pyrazol moiety via tandem coupling–cyclization process, has been developed to afford pyrano[4,3-c]pyrazol-4(1H)-one in a single pot.
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Affiliation(s)
- Dhilli Rao Gorja
- Institute of Science and Technology, JNT University, Kukatpally, Hyderabad 500072, India
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1432
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Molander GA, Sandrock DL. Potassium trifluoroborate salts as convenient, stable reagents for difficult alkyl transfers. Curr Opin Drug Discov Devel 2009; 12:811-23. [PMID: 19894192 PMCID: PMC2908178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The past decade has witnessed the emergence of potassium organotrifluoroborates as a new class of nucleophilic boron reagents for Suzuki-Miyaura cross-coupling and Rh-catalyzed addition reactions. Potassium organotrifluoroborates are easily prepared, and most are indefinitely stable to air and moisture. Recent advances have focused on the utility of alkyltrifluoroborates in appending alkyl groups selectively and conveniently onto appropriate molecular substructures. This review describes strategies employing these reagents as nucleophilic substrates.
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Affiliation(s)
- Gary A Molander
- University of Pennsylvania, Department of Chemistry, 231 S 34th Street, Philadelphia, PA 19104-6323, USA.
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1433
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Layek M, Lakshmi U, Kalita D, Barange DK, Islam A, Mukkanti K, Pal M. Pd/C-mediated synthesis of indoles in water. Beilstein J Org Chem 2009; 5:46. [PMID: 19936266 PMCID: PMC2779661 DOI: 10.3762/bjoc.5.46] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2009] [Accepted: 09/09/2009] [Indexed: 11/23/2022] Open
Abstract
We describe the utility of a Pd/C-Cu mediated method in the synthesis of 2,5-disubstituted indoles in water via a coupling-cyclization strategy. Further application of this methodology has been demonstrated in the preparation of a target indole derivative via a 7-step process the key step being the Pd/C-mediated coupling reaction.
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Affiliation(s)
- Mohosin Layek
- Dr. Reddy's Laboratories Ltd, Bollaram Road, Miyapur, Hyderabad 500049, India
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1434
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Abstract
A catalyst based on a new biarylphosphine ligand (3) for the Pd-catalyzed cross-coupling reactions of amides and aryl chlorides is described. This system shows the highest turnover frequencies reported to date for these reactions, especially for aryl chloride substrates bearing an ortho substituent. An array of amides and aryl chlorides were successfully reacted in good to excellent yields.
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Affiliation(s)
- Brett P. Fors
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Karin Dooleweerdt
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Qingle Zeng
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Stephen L. Buchwald
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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1435
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Reddy EA, Islam A, Mukkanti K, Bandameedi V, Bhowmik DR, Pal M. Regioselective alkynylation followed by Suzuki coupling of 2,4-dichloroquinoline: synthesis of 2-alkynyl-4-arylquinolines. Beilstein J Org Chem 2009; 5:32. [PMID: 19777134 PMCID: PMC2748691 DOI: 10.3762/bjoc.5.32] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 06/19/2009] [Indexed: 11/23/2022] Open
Abstract
A two step synthesis of 2-alkynyl-4-arylquinolines has been accomplished via Pd/C-mediated regioselective C-2 alkynylation of 2,4-dichloroquinoline in water followed by Suzuki coupling at C-4 of the resulting 4-chloro derivative.
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Affiliation(s)
- Ellanki Amarender Reddy
- Dr. Reddy's Laboratories Limited, Bollaram Road, Miyapur, Hyderabad 500049, Andhra Pradesh, India
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1436
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Joshi RK, Krishnan S, Yoshimura M, Kumar A. Pd Nanoparticles and Thin Films for Room Temperature Hydrogen Sensor. Nanoscale Res Lett 2009; 4:1191-1196. [PMID: 20596429 PMCID: PMC2894097 DOI: 10.1007/s11671-009-9379-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Accepted: 06/15/2009] [Indexed: 05/23/2023]
Abstract
We report the application of palladium nanoparticles and thin films for hydrogen sensor. Electrochemically grown palladium particles with spherical shapes deposited on Si substrate and sputter deposited Pd thin films were used to detect hydrogen at room temperature. Grain size dependence of H(2) sensing behavior has been discussed for both types of Pd films. The electrochemically grown Pd nanoparticles were observed to show better hydrogen sensing response than the sputtered palladium thin films. The demonstration of size dependent room temperature H(2) sensing paves the ways to fabricate the room temperature metallic and metal-metal oxide semiconductor sensor by tuning the size of metal catalyst in mixed systems. H(2) sensing by the Pd nanostructures is attributed to the chemical and electronic sensitization mechanisms.
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Affiliation(s)
- Rakesh K Joshi
- Department of Mechanical Engineering, University of South Florida, 4202 E. Fowler Ave., Tampa, FL, 33620, USA
| | - Subramanian Krishnan
- Clean Energy Research Center, University of South Florida, 4202 E. Fowler Ave., Tampa, FL, 33620, USA
| | - Mashamichi Yoshimura
- Nano High Tech Research Centre, Toyota Technological Institute, Hisakata 2-Chome, Tempaku-Ku, Nagoya, 4688511, Japan
| | - Ashok Kumar
- Department of Mechanical Engineering, University of South Florida, 4202 E. Fowler Ave., Tampa, FL, 33620, USA
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1437
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Mennecke K, Kirschning A. Polyionic polymers--heterogeneous media for metal nanoparticles as catalyst in Suzuki-Miyaura and Heck-Mizoroki reactions under flow conditions. Beilstein J Org Chem 2009; 5:21. [PMID: 19590749 PMCID: PMC2707061 DOI: 10.3762/bjoc.5.21] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2009] [Accepted: 04/28/2009] [Indexed: 11/23/2022] Open
Abstract
The preparation of monolithic polyionic supports which serve as efficient heterogeneous supports for palladium(0) nanoparticles is described. These functionalized polymers were incorporated inside a flow reactor and employed in Suzuki-Miyaura and Heck cross couplings under continuous flow conditions.
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Affiliation(s)
- Klaas Mennecke
- Institut für Organische Chemie and Zentrum für Biomolekulare Wirkstoffe (BMWZ), Leibniz Universität Hannover, Schneiderberg 1B, D-30167 Hannover, Germany
| | - Andreas Kirschning
- Institut für Organische Chemie and Zentrum für Biomolekulare Wirkstoffe (BMWZ), Leibniz Universität Hannover, Schneiderberg 1B, D-30167 Hannover, Germany
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1438
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Abstract
In the past decade, palladium-catalyzed C-H activation/C-C bond-forming reactions have emerged as promising new catalytic transformations; however, development in this field is still at an early stage compared to the state of the art in cross-coupling reactions using aryl and alkyl halides. This Review begins with a brief introduction of four extensively investigated modes of catalysis for forming C-C bonds from C-H bonds: Pd(II)/Pd(0), Pd(II)/Pd(IV), Pd(0)/Pd(II)/Pd(IV), and Pd(0)/Pd(II) catalysis. A more detailed discussion is then directed towards the recent development of palladium(II)-catalyzed coupling of C-H bonds with organometallic reagents through a Pd(II)/Pd(0) catalytic cycle. Despite the progress made to date, improving the versatility and practicality of this new reaction remains a tremendous challenge.
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Affiliation(s)
- Xiao Chen
- K. M. Engle, D.-H. Wang, Prof. Dr. J.-Q. Yu, Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037 (USA), Fax: (+1) 858-784-2409, , Dr. X. Chen, Chemical Development Department, Albany Molecular Research, Inc., 21 Corporate Circle, Albany, NY 12203 (USA)
| | - Keary M. Engle
- K. M. Engle, D.-H. Wang, Prof. Dr. J.-Q. Yu, Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037 (USA), Fax: (+1) 858-784-2409, , Dr. X. Chen, Chemical Development Department, Albany Molecular Research, Inc., 21 Corporate Circle, Albany, NY 12203 (USA)
| | - Dong-Hui Wang
- K. M. Engle, D.-H. Wang, Prof. Dr. J.-Q. Yu, Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037 (USA), Fax: (+1) 858-784-2409, , Dr. X. Chen, Chemical Development Department, Albany Molecular Research, Inc., 21 Corporate Circle, Albany, NY 12203 (USA)
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1439
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Abstract
Attempts to introduce the highly versatile vinyl group into other organic molecules in a chemo-, regio- and stereoselective fashion via catalytic activation of ethylene provided challenging opportunities to explore new ligand and salt effects in homogeneous catalysis. This review provides a personal account of the development of enantioselective reactions involving ethylene.
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Affiliation(s)
- T V Rajanbabu
- Department of Chemistry, 100 W. 18 Avenue, The Ohio State University, Columbus, OHIO 43210, USA
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1440
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Stadlmayr W, Penner S, Klötzer B, Memmel N. Growth, thermal stability and structure of ultrathin Zn-layers on Pd(1 1 1). Surf Sci 2009; 603:251-255. [PMID: 20953413 PMCID: PMC2938191 DOI: 10.1016/j.susc.2008.11.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 11/18/2008] [Indexed: 05/29/2023]
Abstract
Low-energy ion scattering with monolayer sensitivity was applied to investigate ultrathin films of zinc on Pd(1 1 1). Uptake curves taken at 150 K indicate the simultaneous growth of multilayers with negligible interlayer transport. Annealing experiments for two-monolayer films reveal a rapid decrease in the zinc content on the surface layer at temperatures above 300 K, forming a metastable state with a Pd:Zn surface ratio of approx. 1:1 in the temperature region between 400 and 550 K. This state is most easily explained as a slightly buckled p(2 × 1)-PdZn surface alloy, with Zn atoms located approx. 0.25 Å above their Pd counterparts.
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Affiliation(s)
| | | | | | - Norbert Memmel
- Corresponding author. Tel.: +43 512 507 5073; fax: +43 512 507 2925.
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1441
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Tsang WCP, Munday RH, Brasche G, Zheng N, Buchwald SL. Palladium-catalyzed method for the synthesis of carbazoles via tandem C-H functionalization and C-N bond formation. J Org Chem 2008; 73:7603-10. [PMID: 18761437 PMCID: PMC2748774 DOI: 10.1021/jo801273q] [Citation(s) in RCA: 227] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of a new method for the assembly of unsymmetrical carbazoles is reported. The strategy involves the selective intramolecular functionalization of an arene C-H bond and the formation of a new arene C-N bond. The substitution pattern of the carbazole product can be controlled by the design of the biaryl amide substrate, and the method is compatible with a variety of functional groups. The utility of the new protocol was demonstrated by the concise synthesis of three natural products from commercially available materials.
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Affiliation(s)
- W. C. Peter Tsang
- Department of Chemistry, Massachusetts Institute of Technology Cambridge, Massachusetts 02139
| | - Rachel H. Munday
- Department of Chemistry, Massachusetts Institute of Technology Cambridge, Massachusetts 02139
| | - Gordon Brasche
- Department of Chemistry, Massachusetts Institute of Technology Cambridge, Massachusetts 02139
| | - Nan Zheng
- Department of Chemistry, Massachusetts Institute of Technology Cambridge, Massachusetts 02139
| | - Stephen L. Buchwald
- Department of Chemistry, Massachusetts Institute of Technology Cambridge, Massachusetts 02139
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1442
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Coudray L, Montchamp JL. Green, Palladium-Catalyzed Synthesis of Benzylic H-phosphinates from Hypophosphorous Acid and Benzylic Alcohols. European J Org Chem 2008; 2008:4101-4103. [PMID: 23349619 PMCID: PMC3551600 DOI: 10.1002/ejoc.200800581] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2008] [Indexed: 11/10/2022]
Abstract
Benzylic alcohols cross-couple directly with concentrated H(3)PO(2) using Pd/xantphos (1 or 2 mol-%). Depending on the substrate, DMF at 110°C, or t-AmOH at reflux with a Dean-Stark trap, can be used. A broad range of benzylic alcohols reacted successfully in moderate to good yields. The preparation of other organophosphorus compounds (phosphinic and phosphonic acids) is also demonstrated.Asymmetric reaction with (R)-1-(2-naphthyl)ethanol provided the corresponding H-phosphinic acid in 77% ee. The methodology provides a green, PCl(3)-free, entry into benzylic-H-phosphinic acids.
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Affiliation(s)
- Laëtitia Coudray
- Department of Chemistry, Texas Christian University, Box 298860, Fort Worth, Texas 76129, USA, Fax: :(+1)-817-257-5851
| | - Jean-Luc Montchamp
- Department of Chemistry, Texas Christian University, Box 298860, Fort Worth, Texas 76129, USA, Fax: :(+1)-817-257-5851
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1443
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Abstract
In the cross-coupling reactions of unprotected oxindoles with aryl halides, Pd- and Cu-based catalyst systems displayed orthogonal chemoselectivity. A Pd-dialkylbiarylphosphine-based catalyst system chemoselectively arylated oxindole at the 3 position, while arylation occurred exclusively at the nitrogen using a Cu-diamine-based catalyst system. Computational examination of the relevant L1Pd(Ar)(oxindolate) and diamine-Cu(oxindolate) species was performed to gain mechanistic insight into the controlling features of the observed chemoselectivity.
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Affiliation(s)
- Ryan A. Altman
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Alan M. Hyde
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Xiaohua Huang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Stephen L. Buchwald
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
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1444
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Affiliation(s)
| | - Stephen L. Buchwald
- Dr. J. García-Fortanet, Prof. Dr. S. L. Buchwald Department of Chemistry, Room 18-490 Massachusetts Institute of Technology Cambridge MA 02139 (USA) Fax: (+) 617-253-3297
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1445
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Abstract
Palladium-catalyzed amination reactions of aryl halides have undergone rapid development in the last 12 years, largely driven by the implementation of new classes of ligands. Biaryl phosphanes have proven to provide especially active catalysts in this context. This Review discusses the application of these catalysts in C-N cross-coupling reactions in the synthesis of heterocycles and pharmaceuticals, in materials science, and in natural product synthesis.
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Affiliation(s)
- David S Surry
- Department of Chemistry, Room 18-490, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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1446
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Affiliation(s)
- Yasumasa Iwai
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112 (USA)
| | - Keith M. Gligorich
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112 (USA)
| | - Matthew S. Sigman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112 (USA)
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1447
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Vignolle J, Gornitzka H, Donnadieu B, Bourissou D, Bertrand G. Palladium-oxygen and palladium-arene interactions in complexes derived from biaryl aminocarbenes: comparison with biaryl phosphanes. Angew Chem Int Ed Engl 2008; 47:2271-4. [PMID: 18273845 PMCID: PMC2440682 DOI: 10.1002/anie.200704927] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | | | | | - Didier Bourissou
- Dr. J. Vignolle, Dr. H. Gornitzka, Dr. D. Bourissou, Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée, UMR–CNRS 5069, 118, route de Narbonne, 31062 Toulouse cedex 09 (France), Fax: (+33)5-6155-8204, E-mail: . Dr. J. Vignolle, B. Donnadieu, Prof. C. Bertrand, UCR–CNRS Joint Research Chemistry Laboratory (UMI 2957), Department of Chemistry, University of California, Riverside, CA 92521-0403 (USA), Fax: (+1)951-827-2725, E-mail:
| | - Guy Bertrand
- Dr. J. Vignolle, Dr. H. Gornitzka, Dr. D. Bourissou, Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée, UMR–CNRS 5069, 118, route de Narbonne, 31062 Toulouse cedex 09 (France), Fax: (+33)5-6155-8204, E-mail: . Dr. J. Vignolle, B. Donnadieu, Prof. C. Bertrand, UCR–CNRS Joint Research Chemistry Laboratory (UMI 2957), Department of Chemistry, University of California, Riverside, CA 92521-0403 (USA), Fax: (+1)951-827-2725, E-mail:
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1448
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He XJ, Shen ZL, Mo WM, Hu BX, Sun N. Asymmetric Glyoxylate-Ene Reactions Catalyzed by Chiral Pd(II) Complexes in the Ionic Liquid [bmim][PF 6]. Int J Mol Sci 2007. [PMCID: PMC3714615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
The room temperature ionic liquid [bmim][PF6] was employed as the reaction medium in the asymmetric glyoxylate-ene reaction of α-methyl styrene (4a) with ethyl glyoxylate using chiral palladium(II) complexes as the catalysts. [Pd(S-BINAP)(3,5-CF3-PhCN)2](SbF6)2 (1b) showed the highest catalytic activity. Under the reaction conditions of 40 °C, 0.5 h, and 1b/4a molar ratio of 0.05, ethyl α-hydroxy-4-phenyl-4-pentenoate was obtained in excellent chemical yield (94 %) with high enantioselectivity (70 %). Other α-hydroxy esters can also be obtained in high chemical yields and enantioselectities through the glyoxylate-ene reactions of alkenes with glyoxylates catalyzed by 1b in [bmim][PF6]. Moreover, the ionic liquid [bmim][PF6] which contained the palladium(II) complex could be recycled and reused several times without significant loss of the catalytic activity.
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Affiliation(s)
| | - Zhen Lu Shen
- Author to whom correspondence should be addressed; Tel. / Fax: 86-571-88320416; E-mail:
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1449
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Wolfe JP. Palladium-Catalyzed Carboetherification and Carboamination Reactions of γ-Hydroxy- and γ-Aminoalkenes for the Synthesis of Tetrahydrofurans and Pyrrolidines. European J Org Chem 2007; 2007:571-582. [PMID: 20577649 PMCID: PMC2890284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Substituted tetrahydrofuran and pyrrolidine moieties are displayed in a wide range of interesting biologically active molecules. The Pd-catalyzed carboetherification or carboamination of γ-hydroxy- and γ-aminoalkenes is a powerful tool for the construction of these heterocycles, as it is convergent and can allow access to a variety of analogs from a single γ-hydroxy- or γ-aminoalkene starting material. This microreview describes the current state of this field.
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Affiliation(s)
- John P Wolfe
- University of Michigan, Department of Chemistry, Ann Arbor, MI 48109-1055 (USA)
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1450
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Sykes ECH, Fernández-Torres LC, Nanayakkara SU, Mantooth BA, Nevin RM, Weiss PS. Observation and manipulation of subsurface hydride in Pd[111] and its effect on surface chemical, physical, and electronic properties. Proc Natl Acad Sci U S A 2005; 102:17907-11. [PMID: 16322103 PMCID: PMC1312391 DOI: 10.1073/pnas.0506657102] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Indexed: 11/18/2022] Open
Abstract
We report the observation and manipulation of hydrogen atoms beneath the surface of a Pd[111] crystal by using low-temperature scanning tunneling microscopy. These subsurface hydride sites have been postulated to have critical roles in hydrogen storage, metal embrittlement, fuel cells, and catalytic reactions, but they have been neither observed directly nor selectively populated previously. We demonstrate that the subsurface region of Pd can be populated with hydrogen atoms from the bulk by applying voltage pulses from a scanning tunneling microscope tip. This phenomenon is explained with an inelastic excitation mechanism, whereby hydrogen atoms in the bulk are excited by tunneling electrons and are promoted to more stable sites in the subsurface region. We show that this selectively placed subsurface hydride affects the electronic, geometric, and chemical properties of the surface. Specifically, we observed the effects of hydride formation on surface deformation and charge and on adsorbed hydrogen on the surface. Hydrogen segregation and overlayer vacancy ordering on the Pd[111] have been characterized and explained in terms of the surface changes attributable to selective hydrogen occupation of subsurface hydride sites in Pd[111].
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Affiliation(s)
- E Charles H Sykes
- Department of Chemistry, Pennsylvania State University, University Park, 16802-6300, USA
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