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Davison N, Hemingway JM, Waddell PG, Lu E. Lithium, sodium and potassium enolate aggregates and monomers: syntheses and structures. Dalton Trans 2024; 53:4719-4728. [PMID: 38362928 DOI: 10.1039/d4dt00211c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
In this Article, we report the syntheses and comparative structural studies of lithium, sodium, and potassium anthracen-9-yl enolates, as their aggregates (Li, Na: hexamer; K: tetramer) and ligand-stabilized monomers (for Li and Na). The monomers add new members to the rare collection of group-1 metal monomeric enolates. Moreover, the series covers different group-1 metal cations (Li+, Na+ and K+) and aggregate sizes, allowing comparative structural studies to elucidate how the metal identity and aggregate size influence the enolate structure.
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Affiliation(s)
- Nathan Davison
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
| | - Jack M Hemingway
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
| | - Paul G Waddell
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
| | - Erli Lu
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
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2
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Koizumi J, Tanaka K, Fukaya K, Urabe D. Stereocontrolled Synthesis of C20 S-C26 and C20 R-C26 Fragments of Amphidinolide L. J Org Chem 2022; 87:11185-11195. [PMID: 35948026 DOI: 10.1021/acs.joc.2c01497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Amphidinolide L is a cytotoxic macrolide isolated from marine symbiotic dinoflagellates of the genus Amphidinium. While its planar structure and the absolute stereochemistry of the C21-C26 part have been determined, six stereocenters have remained unassigned. Aiming at structure determination, we have developed a synthetic route to the C20S-C26 and C20R-C26 fragments via the Li-mediated stereocontrolled aldol reaction. Two aldehydes, 16 with the C22-hydroxy group and 19 with the C22-TES ether, were synthesized from lactone 4. The aldol reactions using the Li-enolate of 4-methyl-2-pentanone in THF provided the C20S-C26 fragment 20 from 16 and a 1:3.5 mixture of the C20-C26 fragment 22 favoring the C20R-isomer. Mechanistic studies based on an extensive search of transition states in explicit solvents indicated that the C20S-isomer would be generated via a tri-solvated transition state, while the C20R-isomer would be formed via a di-solvated transition state. The calculation emphasizes the importance of the coordination network as a higher-order complex composed of solvent molecules, aldehyde, enolate, and Li atoms in the reaction of 16 to minimize steric interactions but maximize the stabilizing effect by the coordination of solvents. The presence of the rotationally free aldehyde in the reaction of 19 results in moderate diastereoselectivity.
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Affiliation(s)
- Jun Koizumi
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Kaoru Tanaka
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Keisuke Fukaya
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Daisuke Urabe
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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3
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Mulvey RE, Lynch JR, Kennedy AR, Barker J, Reid J. Crystallographic Characterisation of Organolithium and Organomagnesium Intermediates in Reactions of Aldehydes and Ketones. Helv Chim Acta 2022. [DOI: 10.1002/hlca.202200082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Robert E. Mulvey
- University of Strathclyde Pure and Applied Chemistry 295 Cathedral Street G1 1XL Glasgow UNITED KINGDOM
| | | | - Alan R. Kennedy
- University of Strathclyde Pure and Applied Chemistry UNITED KINGDOM
| | - Jim Barker
- Innospec Ltd Research and Technology UNITED KINGDOM
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4
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Zhang Z, Collum DB. Structures and Reactivities of Sodiated Evans Enolates: Role of Solvation and Mixed Aggregation on the Stereochemistry and Mechanism of Alkylations. J Am Chem Soc 2019; 141:388-401. [PMID: 30462500 PMCID: PMC7185956 DOI: 10.1021/jacs.8b10364] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxazolidinone-based sodiated enolates (Evans enolates) were generated using sodium diisopropylamide (NaDA) or sodium hexamethyldisilazide (NaHMDS) in the presence of N,N,N',N'-tetramethylethylenediamine (TMEDA), ( R,R)- trans- N,N,N',N'-tetramethylcyclohexanediamine [( R,R)-TMCDA], or ( S,S)-TMCDA. 13C NMR spectroscopic analysis in conjunction with the method of continuous variations (MCV), x-ray crystallography, and density functional theory (DFT) computations revealed the enolates to be octahedral bis-diamine-chelated monomers. Rate and computational studies of an alkylation with allyl bromide implicate a bis-diamine-chelated-monomer-based transition structure. The sodiated Evans enolates form mixed dimers with NaHMDS, NaDA, or sodium 2,6-di- tert-butylphenolate, the reactivities of which are examined. Stereoselective quaternizations, aldol additions, and azaaldol additions are described.
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Affiliation(s)
- Zirong Zhang
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301
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5
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Jermaks J, Tallmadge EH, Keresztes I, Collum DB. Lithium Amino Alkoxide-Evans Enolate Mixed Aggregates: Aldol Addition with Matched and Mismatched Stereocontrol. J Am Chem Soc 2018; 140:3077-3090. [PMID: 29457718 PMCID: PMC6059615 DOI: 10.1021/jacs.7b13776] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Building on structural and mechanistic studies of lithiated enolates derived from acylated oxazolidinones (Evans enolates) and chiral lithiated amino alkoxides, we found that amino alkoxides amplify the enantioselectivity of aldol additions. The pairing of enantiomeric series affords matched and mismatched stereoselectivities. The structures of mixed tetramers showing 2:2 and 3:1 (alkoxide-rich) stoichiometries are determined spectroscopically. Rate and computational studies provide a viable mechanistic and stereochemical model based on the direct reaction of the 3:1 mixed tetramers, but they raise unanswered questions for the 2:2 mixed aggregates.
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Affiliation(s)
- Janis Jermaks
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - Evan H. Tallmadge
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - Ivan Keresztes
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
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6
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Lahosa A, Soler T, Arrieta A, Cossío FP, Foubelo F, Yus M. Stereoselective Coupling of N-tert-Butanesulfinyl Aldimines and β-Keto Acids: Access to β-Amino Ketones. J Org Chem 2017; 82:7481-7491. [PMID: 28661149 DOI: 10.1021/acs.joc.7b01178] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The reaction of chiral N-tert-butanesulfinyl aldimines with β-keto acids under basic conditions at room temperature proceeds with high levels of diastereocontrol, leading to β-amino ketones in high yields. Based on DFT calculations, an eight-membered cyclic transition state involving coordination of the lithium atom to the oxygens of carboxylate and sulfinyl units was proposed, being in agreement with the observed experimental diastereomeric ratios. The synthesis of the piperidine alkaloid (-)-pelletierine was successfully undertaken in order to demonstrate the utility of this methodology.
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Affiliation(s)
- Alejandro Lahosa
- Departamento de Química Orgánica, Facultad de Ciencias, and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante , Apdo. 99, 03080 Alicante, Spain.,Instituto de Síntesis Orgánica (ISO), Universidad de Alicante , Apdo. 99, 03080 Alicante, Spain
| | - Tatiana Soler
- Servicios Técnicos de Investigación, Universidad de Alicante , Apdo. 99, 03080 Alicante, Spain
| | - Ana Arrieta
- Departamento de Quı́mica Organica I and Centro de Innovación en Química Avanzada (ORFEO CINQA), University of the Basque Country (UPV/EHU) , P° Manuel Lardizabal 3, 20018 Donostia/San Sebastian, Spain
| | - Fernando P Cossío
- Departamento de Quı́mica Organica I and Centro de Innovación en Química Avanzada (ORFEO CINQA), University of the Basque Country (UPV/EHU) , P° Manuel Lardizabal 3, 20018 Donostia/San Sebastian, Spain
| | - Francisco Foubelo
- Departamento de Química Orgánica, Facultad de Ciencias, and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante , Apdo. 99, 03080 Alicante, Spain.,Instituto de Síntesis Orgánica (ISO), Universidad de Alicante , Apdo. 99, 03080 Alicante, Spain
| | - Miguel Yus
- Departamento de Química Orgánica, Facultad de Ciencias, and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante , Apdo. 99, 03080 Alicante, Spain
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7
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Guang J, Liu Q, Hopson R, Kagan G, Li W, Monroe TB, Williard PG. Conformational Polymorphism of Lithium Pinacolone Enolate. J Am Chem Soc 2016; 138:15177-15188. [PMID: 27762552 DOI: 10.1021/jacs.6b08177] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A metastable, polymorphic hexameric crystal structure of lithium pinacolone enolate (LiOPin) is reported along with three preparation methods. NMR-based structural characterization implies that the lithium pinacolate hexamer deaggregates to a tetramer in toluene but retains mainly the hexameric structure in nonaromatic hydrocarbon solvents such as cyclohexane. Moreover, the presence of a small amount of lithium aldolate (LiOA) dramatically influences the aggregation state of LiOPin by forming a mixed aggregate with a 3:1 ratio (LiOPin3·LiOA).
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Affiliation(s)
- Jie Guang
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Qiyong Liu
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Russell Hopson
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Gerald Kagan
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Weibin Li
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Thomas B Monroe
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Paul G Williard
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
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8
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Honda K, Harris TV, Hatanaka M, Morokuma K, Mikami K. Computational S
N
2‐Type Mechanism for the Difluoromethylation of Lithium Enolate with Fluoroform through Bimetallic C−F Bond Dual Activation. Chemistry 2016; 22:8796-800. [DOI: 10.1002/chem.201601090] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Kazuya Honda
- Department of Applied Chemistry Tokyo Institute of Technology Tokyo 152-8552 Japan
| | - Travis V. Harris
- Fukui Institute for Fundamental Chemistry Kyoto University Kyoto 606-8103 Japan
- Department of Chemistry University of Puget Sound Tacoma Washington 98416 USA
| | - Miho Hatanaka
- Fukui Institute for Fundamental Chemistry Kyoto University Kyoto 606-8103 Japan
- Department of Chemistry Faculty of Science and Engineering Kinki University Osaka 577-8502 Japan
| | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry Kyoto University Kyoto 606-8103 Japan
| | - Koichi Mikami
- Department of Applied Chemistry Tokyo Institute of Technology Tokyo 152-8552 Japan
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9
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Tallmadge EH, Jermaks J, Collum DB. Structure-Reactivity Relationships in Lithiated Evans Enolates: Influence of Aggregation and Solvation on the Stereochemistry and Mechanism of Aldol Additions. J Am Chem Soc 2016; 138:345-55. [PMID: 26639525 PMCID: PMC4762877 DOI: 10.1021/jacs.5b10980] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Aldol additions to isobutyraldehyde and cyclohexanone with lithium enolates derived from acylated oxazolidinones (Evans enolates) are described. Previously characterized trisolvated dimeric enolates undergo rapid addition to isobutyraldehyde to give a 12:1 syn:syn selectivity in high yield along with small amounts of one anti isomer. The efficacy of the addition depends critically on aging effects and the reaction quench. Unsolvated tetrameric enolates that form on warming the solutions are unreactive toward isobutyraldehyde and undergo retroaldol reaction under forcing conditions. Additions to cyclohexanone are relatively slow but form a single isomeric adduct in >80% yield. The ketone-derived aldolates are robust. All attempts to control stereoselectivity by controlling aggregation failed. Rate studies of addition to cyclohexanone trace the lack of aggregation-dependent selectivities to a monomer-based mechanism. The synthetic implications and possible utility of lithium enolates in Evans aldol additions are discussed.
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Affiliation(s)
- Evan H. Tallmadge
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - Janis Jermaks
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
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10
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Jin KJ, Collum DB. Solid-State and Solution Structures of Glycinimine-Derived Lithium Enolates. J Am Chem Soc 2015; 137:14446-55. [PMID: 26554898 PMCID: PMC4762874 DOI: 10.1021/jacs.5b09524] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A combination of crystallographic, spectroscopic, and computational studies was applied to study the structures of lithium enolates derived from glycinimines of benzophenone and (+)-camphor. The solvents examined included toluene and toluene containing various concentrations of tetrahydrofuran, N,N,N',N'-tetramethylethylenediamine (TMEDA), (R,R)-N,N,N',N'-tetramethylcyclohexanediamine [(R,R)-TMCDA], and (S,S)-N,N,N',N'-tetramethylcyclohexanediamine [(S,S)-TMCDA]. Crystal structures show chelated monomers, symmetric disolvated dimers, S4-symmetric tetramers, and both S6- and D3d-symmetric hexamers. (6)Li NMR spectroscopic studies in conjunction with the method of continuous variations show how these species distribute in solution. Density functional theory computations offer insights into experimentally elusive details.
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Affiliation(s)
- Kyoung Joo Jin
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
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11
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Tallmadge EH, Collum DB. Evans Enolates: Solution Structures of Lithiated Oxazolidinone-Derived Enolates. J Am Chem Soc 2015; 137:13087-95. [PMID: 26437278 PMCID: PMC4765922 DOI: 10.1021/jacs.5b08207] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The results of a combination of (6)Li and (13)C NMR spectroscopic and computational studies of oxazolidinone-based lithium enolates-Evans enolates-in tetrahydrofuran (THF) solution revealed a mixture of dimers, tetramers, and oligomers (possibly ladders). The distribution depended on the structure of the oxazolidinone auxiliary, substituent on the enolate, and THF concentration (in THF/toluene mixtures). The unsolvated tetrameric form contained a D(2d)-symmetric core structure, whereas the dimers were determined experimentally and computationally to be trisolvates with several isomeric forms.
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Affiliation(s)
- Evan H Tallmadge
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853-1301, United States
| | - David B Collum
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853-1301, United States
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12
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Rousseau G, Lebeuf R, Schenk K, Castet F, Robert F, Landais Y. Base-catalyzed intramolecular hydroamination of cyclohexa-2,5-dienes: insights into the mechanism through DFT calculations and application to the total synthesis of epi-elwesine. Chemistry 2014; 20:14771-82. [PMID: 25223607 DOI: 10.1002/chem.201403662] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/10/2014] [Indexed: 11/08/2022]
Abstract
The base-catalyzed intramolecular hydroamination of 1-ethylaminocyclohexa-2,5-dienes is described. The transformation proceeds through isomerization of the cyclohexa-1,4-dienyl fragment into the corresponding conjugated 1,3-diene prior to the hydroamination step. Attaching a chiral glycinol ether auxiliary on the amino group allows the protonation to occur with complete diastereocontrol. The resulting lithium amide then adds onto the 1,3-dienyl moiety, affording the desired fused pyrrolidine ring along with the corresponding lithium allylic anion. Protonation of the latter then proceeds with high regiocontrol to favor the resulting allylic amines. In contrast, when the reaction was performed on primary amines, fused pyrrolidines bearing a homoallylic amino group were obtained. The stereochemical course of the process and determination of the reaction pathways were established based on calculations performed at the DFT level. Finally, application of the methodology to the enantioselective synthesis of (+)-epi-elwesine, a crinane alkaloid, is described.
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Affiliation(s)
- Géraldine Rousseau
- ISM, UMR 5255, University of Bordeaux and CNRS, 351, Cours de la liberation, 33400 Talence Cedex (France)
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13
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Ward DE, Kundu D, Biniaz M, Jana S. A Systematic Study of the Effects of Relative Configuration, Protecting Group, and Enolate Type on the Diastereoselectivities of Aldol Reactions of a Chiral Ethyl Ketone with 2-Methylpropanal. J Org Chem 2014; 79:6868-94. [DOI: 10.1021/jo500927x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dale E. Ward
- Department of Chemistry, University of Saskatchewan, 110
Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Diptarghya Kundu
- Department of Chemistry, University of Saskatchewan, 110
Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Mojtaba Biniaz
- Department of Chemistry, University of Saskatchewan, 110
Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Sushital Jana
- Department of Chemistry, University of Saskatchewan, 110
Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
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14
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Real Sociedad Española de Química Prizes 2013. Angew Chem Int Ed Engl 2013; 52:11454-5. [DOI: 10.1002/anie.201307962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Ehrungen der Real Sociedad Española de Química. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201307962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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