151
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Shrestha R, Weix DJ. Reductive conjugate addition of haloalkanes to enones to form silyl enol ethers. Org Lett 2011; 13:2766-9. [PMID: 21491901 DOI: 10.1021/ol200881v] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new method is presented for tandem reductive conjugate addition and silyl enol ether formation from cyclic and acyclic enones and enals in the presence of a Mn reductant, a Ni(terpyridine) catalyst, and a trialkylchlorosilane. The addition of secondary, tertiary, and hindered primary haloalkanes is demonstrated. Preliminary studies on the mechanism show that the intermediacy of L1(Ni)(η(3)-1-triethylsilyloxyalkenyl)X or in-situ-formed RMnX is unlikely.
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Affiliation(s)
- Ruja Shrestha
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
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152
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Romine JL, St. Laurent DR, Leet JE, Martin S, Serrano-Wu MH, Yang F, Gao M, O’Boyle D, Lemm JA, Sun JH, Nower PT, Huang X(S, Deshpande MS, Meanwell NA, Snyder LB. Inhibitors of HCV NS5A: From Iminothiazolidinones to Symmetrical Stilbenes. ACS Med Chem Lett 2011; 2:224-9. [PMID: 24900306 PMCID: PMC4017990 DOI: 10.1021/ml1002647] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 12/20/2010] [Indexed: 12/20/2022] Open
Abstract
The iminothiazolidinone BMS-858 (2) was identified as a specific inhibitor of HCV replication in a genotype 1b replicon assay via a high-throughput screening campaign. A more potent analogue, BMS-824 (18), was used in resistance mapping studies, which revealed that inhibitory activity was related to disrupting the function of the HCV nonstructural protein 5A. Despite the development of coherent and interpretable SAR, it was subsequently discovered that in DMSO 18 underwent an oxidation and structural rearrangement to afford the thiohydantoin 47, a compound with reduced HCV inhibitory activity. However, HPLC bioassay fractionation studies performed after incubation of 18 in assay media led to the identification of fractions containing a dimeric species 48 that exhibited potent antiviral activity. Excision of the key elements hypothesized to be responsible for antiviral activity based on SAR observations reduced 48 to a simplified, symmetrical, pharmacophore realized most effectively with the stilbene 55, a compound that demonstrated potent inhibition of HCV in a genotype 1b replicon with an EC50 = 86 pM.
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Affiliation(s)
- Jeffrey L. Romine
- Department of Discovery
Chemistry, Bristol-Myers Squibb Research
and Development, 5 Research Parkway, Wallingford, Connecticut
06492, United States
| | - Denis R. St. Laurent
- Department of Discovery
Chemistry, Bristol-Myers Squibb Research
and Development, 5 Research Parkway, Wallingford, Connecticut
06492, United States
| | - John E. Leet
- Synthesis & Analysis Technology
Team, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Scott
W. Martin
- Department of Discovery
Chemistry, Bristol-Myers Squibb Research
and Development, 5 Research Parkway, Wallingford, Connecticut
06492, United States
| | - Michael H. Serrano-Wu
- Department of Discovery
Chemistry, Bristol-Myers Squibb Research
and Development, 5 Research Parkway, Wallingford, Connecticut
06492, United States
| | - Fukang Yang
- Department of Discovery
Chemistry, Bristol-Myers Squibb Research
and Development, 5 Research Parkway, Wallingford, Connecticut
06492, United States
| | - Min Gao
- Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Donald
R O’Boyle
- Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Julie A. Lemm
- Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Jin-Hua Sun
- Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Peter T. Nower
- Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Xiaohua (Stella) Huang
- Discovery Analytical Sciences, Bristol-Myers Squibb Research and Development, 5 Research
Parkway, Wallingford, Connecticut 06492, United States
| | - Milind S. Deshpande
- Department of Discovery
Chemistry, Bristol-Myers Squibb Research
and Development, 5 Research Parkway, Wallingford, Connecticut
06492, United States
| | - Nicholas A. Meanwell
- Department of Discovery
Chemistry, Bristol-Myers Squibb Research
and Development, 5 Research Parkway, Wallingford, Connecticut
06492, United States
| | - Lawrence B. Snyder
- Department of Discovery
Chemistry, Bristol-Myers Squibb Research
and Development, 5 Research Parkway, Wallingford, Connecticut
06492, United States
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153
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Litwinienko G, Beckwith ALJ, Ingold KU. The frequently overlooked importance of solvent in free radical syntheses. Chem Soc Rev 2011; 40:2157-63. [PMID: 21344074 DOI: 10.1039/c1cs15007c] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This tutorial review is designed to dispel the myth, still believed by many synthetic organic chemists, that radical-based syntheses are free from significant solvent effects. However, many synthetically valuable radical reactions do exhibit large kinetic solvent effects. It is therefore important to select the solvent for any proposed radical synthesis with considerable care if good product yields are to be achieved.
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154
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Radical cyclizations of acylsilanes in the synthesis of (+)-swainsonine and formal synthesis of (−)-epiquinamide. Tetrahedron 2011. [DOI: 10.1016/j.tet.2010.12.048] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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155
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Lin CY, Peh J, Coote ML. Effects of Chemical Structure on the Thermodynamic Efficiency of Radical Chain Carriers for Organic Synthesis. J Org Chem 2011; 76:1715-26. [DOI: 10.1021/jo102368v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ching Yeh Lin
- ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
| | - Jessie Peh
- ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
| | - Michelle L. Coote
- ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
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156
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A green way to γ-lactams through a copper catalyzed ARGET-ATRC in ethanol and in the presence of ascorbic acid. Tetrahedron 2011. [DOI: 10.1016/j.tet.2010.11.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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157
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Radical Additions to Chiral Hydrazones: Stereoselectivity and Functional Group Compatibility. Top Curr Chem (Cham) 2011; 320:61-91. [DOI: 10.1007/128_2011_163] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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158
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Bakowski A, Dressel M, Bauer A, Bach T. Enantioselective radical cyclisation reactions of 4-substituted quinolones mediated by a chiral template. Org Biomol Chem 2011; 9:3516-29. [DOI: 10.1039/c0ob01272f] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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159
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Beemelmanns C, Reissig HU. Samarium diiodide induced ketyl-(het)arene cyclisations towards novel N-heterocycles. Chem Soc Rev 2011; 40:2199-210. [DOI: 10.1039/c0cs00116c] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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160
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Tsurugi H, Yamada K, Majumdar M, Sugino Y, Hayakawa A, Mashima K. Dinuclear molybdenum cluster-catalyzed radical addition and polymerization reactions by tuning the redox potential of a quadruple bonded Mo2 core. Dalton Trans 2011; 40:9358-61. [PMID: 21850333 DOI: 10.1039/c1dt11129a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Hayato Tsurugi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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161
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Jahn U. Radicals in transition metal catalyzed reactions? transition metal catalyzed radical reactions? a fruitful interplay anyway: part 1. Radical catalysis by group 4 to group 7 elements. Top Curr Chem (Cham) 2011; 320:121-89. [PMID: 22025066 DOI: 10.1007/128_2011_261] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This review summarizes the current status of radical-based transition metal catalyzed reactions in organic chemistry. The underlying features of radical generation from transition metal complexes and radical reactivity in the framework of transition metal catalysis are discussed. The available arsenal to detect radicals in transition metal catalyzed transformations is presented. Available strategies to combine radical intermediates with transition metal catalysis are outlined. In the main part the currently known synthetic methodology of transition metal catalyzed reactions proceeding via radical intermediates is discussed. This part covers catalytic radical reactions involving group 4 to group 7 elements.
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Affiliation(s)
- Ullrich Jahn
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo namesti 2, 16610, Prague 6, Czech Republic.
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162
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Ueda M, Kondoh E, Ito Y, Shono H, Kakiuchi M, Ichii Y, Kimura T, Miyoshi T, Naito T, Miyata O. Benzyl radical addition reaction through the homolytic cleavage of a benzylic C–H bond. Org Biomol Chem 2011; 9:2062-4. [DOI: 10.1039/c0ob01148g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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163
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Stoltz B, Motherwell W. Tetrahedron reports on organic chemistry. Tetrahedron 2010. [DOI: 10.1016/s0040-4020(10)01735-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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164
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Oxidation of Alkyl Trifluoroborates: An Opportunity for Tin-Free Radical Chemistry. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201004513] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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165
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Sorin G, Martinez Mallorquin R, Contie Y, Baralle A, Malacria M, Goddard JP, Fensterbank L. Oxidation of Alkyl Trifluoroborates: An Opportunity for Tin-Free Radical Chemistry. Angew Chem Int Ed Engl 2010; 49:8721-3. [DOI: 10.1002/anie.201004513] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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166
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Pastori N, Greco C, Clerici A, Punta C, Porta O. Free-Radical Addition to Ketimines Generated In Situ. New One-Pot Synthesis of Quaternary α-Aminoamides Promoted by a H2O2/TiCl4−Zn/HCONH2 System. Org Lett 2010; 12:3898-901. [DOI: 10.1021/ol1015916] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nadia Pastori
- Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano-Sezione Chimica, Via Mancinelli 7, 20131 Milano, Italy
| | - Cosimina Greco
- Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano-Sezione Chimica, Via Mancinelli 7, 20131 Milano, Italy
| | - Angelo Clerici
- Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano-Sezione Chimica, Via Mancinelli 7, 20131 Milano, Italy
| | - Carlo Punta
- Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano-Sezione Chimica, Via Mancinelli 7, 20131 Milano, Italy
| | - Ombretta Porta
- Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano-Sezione Chimica, Via Mancinelli 7, 20131 Milano, Italy
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167
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Feng X, Cui HL, Xu S, Wu L, Chen YC. Organocatalytic Direct Vinylogous Michael Addition of α,β-Unsaturated γ-Butyrolactam to α,β-Unsaturated Aldehydes and an Illustration to Scaffold Diversity Synthesis. Chemistry 2010; 16:10309-12. [DOI: 10.1002/chem.201001350] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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168
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Ravelli D, Zema M, Mella M, Fagnoni M, Albini A. Benzoyl radicals from (hetero)aromatic aldehydes. Decatungstate photocatalyzed synthesis of substituted aromatic ketones. Org Biomol Chem 2010; 8:4158-64. [PMID: 20661511 DOI: 10.1039/c0ob00066c] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Benzoyl radicals are generated directly from (hetero)aromatic aldehydes upon tetrabutylammonium decatungstate ((n-Bu(4)N)(4)W(10)O(32)), TBADT) photocatalysis under mild conditions. In the presence of alpha,beta-unsaturated esters, ketones and nitriles radical conjugate addition ensues and gives the corresponding beta-functionalized aryl alkyl ketones in moderate to good yields (stereoselectively in the case of 3-methylene-2-norbornanone). Due to the mild reaction conditions the presence of various functional groups on the aromatic ring is tolerated (e.g. methyl, methoxy, chloro). The method can be applied to hetero-aromatic aldehydes whether electron-rich (e.g. thiophene-2-carbaldehyde) or electron-poor (e.g. pyridine-3-carbaldehyde).
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Affiliation(s)
- Davide Ravelli
- Department of Organic Chemistry, University of Pavia, Viale Taramelli 10, 27100 Pavia, Italy
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169
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Chudasama V, Fitzmaurice RJ, Caddick S. Hydroacylation of α,β-unsaturated esters via aerobic C–H activation. Nat Chem 2010; 2:592-6. [DOI: 10.1038/nchem.685] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Accepted: 04/21/2010] [Indexed: 12/17/2022]
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170
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Pintauer T. Catalyst Regeneration in Transition‐Metal‐Mediated Atom‐Transfer Radical Addition (ATRA) and Cyclization (ATRC) Reactions. Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.201000234] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tomislav Pintauer
- Duquesne University, Department of Chemistry and Biochemistry, 600 Forbes Avenue, 308 Mellon Hall, Pittsburgh, PA 15282, USA, Fax: +1‐412‐396‐5683
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171
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Balili MNC, Pintauer T. Kinetic Studies of the Initiation Step in Copper Catalyzed Atom Transfer Radical Addition (ATRA) in the Presence of Free Radical Diazo Initiators as Reducing Agents. Inorg Chem 2010; 49:5642-9. [DOI: 10.1021/ic100540q] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marielle Nicole C. Balili
- Duquesne University, Department of Chemistry and Biochemistry, 600 Forbes Avenue, 308 Mellon Hall, Pittsburgh, Pennsylvania 15282
| | - Tomislav Pintauer
- Duquesne University, Department of Chemistry and Biochemistry, 600 Forbes Avenue, 308 Mellon Hall, Pittsburgh, Pennsylvania 15282
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172
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