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Ligand-Dominated Activation of CO 2 and CS 2 by the Putative Nickel Phosphiniminato Intermediates. Inorg Chem 2024; 63:7820-7827. [PMID: 38630579 DOI: 10.1021/acs.inorgchem.4c00429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Room-temperature photoactivation of the first- and second-generation PN3P-pincer nickel azido complexes 1a and 1b in the presence of CO2 or CS2 afforded N-bound carbamates, dithiocarbamates, and isothiocyanates, providing insights into CO2 and CS2 activation and demonstrating how a seemingly small difference in the ligand structure significantly influences the reactivity. Theoretical calculations disclosed that the charge of the phosphorus atom plays a critical role in determining the nitrogen atom transfer to form a plausible nickel phosphiniminato intermediate.
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2
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Nitrogen Reduction to Ammonia by a Phosphorus-Nitrogen PN
3
PMo(V) Nitride Complex: Significant Enhancement
via
Ligand Post-Modification. CCS CHEMISTRY 2022. [DOI: 10.31635/ccschem.022.202202385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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3
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Selective benzylic C sp3-H bond activations mediated by a phosphorus-nitrogen PN 3P-nickel complex. Chem Commun (Camb) 2022; 58:1593-1596. [PMID: 35018914 DOI: 10.1039/d1cc06507f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In contrast to the typical Csp2-H activation, a PN3P-Nickel complex chemoselectively cleaved the benzylic Csp3-H bond of toluene in the presence of KHMDS, presumably via an in situ generated potassium benzyl intermediate. Under similar conditions, CO underwent deoxygenation to afford the corresponding nickel cyano complex, and ethylbenzene was dehydrogenated to give styrene and a nickel hydride compound. 2,6-Xylyl isocyanide was transformed into an unprecedented indolyl complex, likely by trapping the activated benzyl species with an isocyanide moiety.
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4
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Understanding Halide Counterion Effects in Enantioselective Ruthenium-Catalyzed Carbonyl (α-Aryl)allylation: Alkynes as Latent Allenes and Trifluoroethanol-Enhanced Turnover in The Conversion of Ethanol to Higher Alcohols via Hydrogen Auto-transfer. J Am Chem Soc 2021; 143:16709-16717. [PMID: 34606271 PMCID: PMC8749865 DOI: 10.1021/jacs.1c07857] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Crystallographic characterization of RuX(CO)(η3-C3H5)(JOSIPHOS), where X = Cl, Br, or I, reveals a halide-dependent diastereomeric preference that defines metal-centered stereogenicity and, therefrom, the enantioselectivity of C-C coupling in ruthenium-catalyzed anti-diastereo- and enantioselective C-C couplings of primary alcohols with 1-aryl-1-propynes to form products of carbonyl anti-(α-aryl)allylation. Computational studies reveal that a non-classical hydrogen bond between iodide and the aldehyde formyl CH bond stabilizes the favored transition state for carbonyl addition. An improved catalytic system enabling previously unattainable transformations was developed that employs an iodide-containing precatalyst, RuI(CO)3(η3-C3H5), in combination with trifluoroethanol, as illustrated by the first enantioselective ruthenium-catalyzed C-C couplings of ethanol to form higher alcohols.
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5
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Redox-Neutral Imination of Alcohol with Azide: A Sustainable Alternative to the Staudinger/Aza-Wittig Reaction. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00379] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Aromaticity in catalysis: metal ligand cooperation via ligand dearomatization and rearomatization. Chem Commun (Camb) 2021; 57:3070-3082. [PMID: 33656025 DOI: 10.1039/d1cc00528f] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Unlike the conventional model of transition metal catalysis, ligands in metal-ligand cooperative (or bifunctional) catalysis are involved in the substrate activations. Such processes have offered unique mechanistic understandings and led to new concepts for the catalyst design. In particular, unprecedented activities were discovered when the ligand could undergo dearomatization-rearomatization reactions during the catalytic cycle. Aromatization can provide an extra driving force to thermodynamics; consequently, it brings a new perspective to ligand platform design for catalysis. While numerous applications were demonstrated, the influences of changing ligand aromatic properties were often overlooked. In this article, representative ligand systems will be highlighted and a comparison between the Milstein and the Huang pincer systems will be discussed to provide theoretical and conceptual insights.
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7
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All-Carbon Quaternary Stereocenters α to Azaarenes via Radical-Based Asymmetric Olefin Difunctionalization. J Am Chem Soc 2020; 142:19451-19456. [DOI: 10.1021/jacs.0c08329] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Mechanistic elucidation of the role of metal oxidation states in nickel mediated electrocatalytic coupling of benzyl halides. GREEN SYNTHESIS AND CATALYSIS 2020. [DOI: 10.1016/j.gresc.2020.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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9
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Asymmetric Three-Component Heck Arylation/Amination of Nonconjugated Cyclodienes. Angew Chem Int Ed Engl 2020; 59:5341-5345. [PMID: 31965664 DOI: 10.1002/anie.201915864] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/21/2020] [Indexed: 12/11/2022]
Abstract
Substituted cyclohexylamines are becoming increasingly important in drug discovery. Asymmetric Heck insertion/amination of nonconjugated cyclodienes proceeds to give 5-aryl cyclohexenylamines with good enantioselectivity and exclusive trans configurations. Primary and secondary anilines, indoline, and benzylamines are suitable amines. The weakly donating diphosphite Kelliphite forms a deep unsymmetrical pocket, which is essential for stereoselective anti attack of amines.
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10
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Asymmetric Three‐Component Heck Arylation/Amination of Nonconjugated Cyclodienes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915864] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Dearomatization of 3‐Nitroindoles by a Phosphine‐Catalyzed Enantioselective [3+2] Annulation Reaction. Angew Chem Int Ed Engl 2019; 58:5427-5431. [DOI: 10.1002/anie.201900248] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Indexed: 02/06/2023]
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12
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Beyond the PN
3
(P) system: Synthesis of non‐symmetrical PONNP‐pincer ligands and a unique Ni–Ag bimetallic complex containing a short Ag–Ag distance. J CHIN CHEM SOC-TAIP 2019. [DOI: 10.1002/jccs.201900024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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Dearomatization of 3‐Nitroindoles by a Phosphine‐Catalyzed Enantioselective [3+2] Annulation Reaction. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201900248] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Cyclometalated Iridium-PhanePhos Complexes Are Active Catalysts in Enantioselective Allene-Fluoral Reductive Coupling and Related Alcohol-Mediated Carbonyl Additions That Form Acyclic Quaternary Carbon Stereocenters. J Am Chem Soc 2019; 141:2087-2096. [PMID: 30681850 PMCID: PMC6423978 DOI: 10.1021/jacs.8b11868] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Iridium complexes modified by the chiral phosphine ligand PhanePhos catalyze the 2-propanol-mediated reductive coupling of diverse 1,1-disubstituted allenes 1a-1u with fluoral hydrate 2a to form CF3-substituted secondary alcohols 3a-3u that incorporate acyclic quaternary carbon-containing stereodiads. By exploiting concentration-dependent stereoselectivity effects related to the interconversion of kinetic ( Z)- and thermodynamic ( E)-σ-allyliridium isomers, adducts 3a-3u are formed with complete levels of branched regioselectivity and high levels of anti-diastereo- and enantioselectivity. The utility of this method for construction of CF3-oxetanes and CF3-azetidines is illustrated by the formation of 4a and 6a, respectively. Studies of the reaction mechanism aimed at illuminating the singular effectiveness of PhanePhos as a supporting ligand in this and related transformations have led to the identification of a chromatographically stable cyclometalated iridium-( R)-PhanePhos complex, Ir-PP-I, that is catalytically competent for allene-fluoral reductive coupling and previously reported transfer hydrogenative C-C couplings of dienes or CF3-allenes with methanol. Deuterium labeling studies, reaction progress kinetic analysis (RPKA) and computational studies corroborate a catalytic mechanism involving rapid allene hydrometalation followed by turnover-limiting carbonyl addition. A computationally determined stereochemical model shows that the ortho-CH2 group of the cyclometalated iridium-PhanePhos complex plays a key role in directing diastereo- and enantioselectivity. The collective data provide key insights into the structural-interactional features of allyliridium complexes required to enforce nucleophilic character, which should inform the design of related cyclometalated catalysts for umpoled allylation.
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16
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Diverse catalytic reactivity of a dearomatized PN 3P*-nickel hydride pincer complex towards CO 2 reduction. Chem Commun (Camb) 2018; 54:11395-11398. [PMID: 30175825 DOI: 10.1039/c8cc05948a] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A dearomatized PN3P*-nickel hydride complex has been prepared using an oxidative addition process. The first nickel-catalyzed hydrosilylation of CO2 to methanol has been achieved, with unprecedented turnover numbers. Selective methylation and formylation of amines with CO2 were demonstrated by such a PN3P*-nickel hydride complex, highlighting its versatile functions in CO2 reduction.
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A Pseudodearomatized PN3P*Ni–H Complex as a Ligand and σ-Nucleophilic Catalyst. J Org Chem 2018; 83:14969-14977. [DOI: 10.1021/acs.joc.8b02205] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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18
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Glaulactams A-C, daphniphyllum alkaloids from Daphniphyllum glaucescens. Sci Rep 2018; 8:15417. [PMID: 30337630 PMCID: PMC6193994 DOI: 10.1038/s41598-018-33748-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 10/07/2018] [Indexed: 02/07/2023] Open
Abstract
Glaulactams A-C (1-3), which possess a novel skeleton, as well as the known compound daphmanidin B (4), were isolated from the leaves of Daphniphyllum glaucescens and separated using ion-exchange chromatography aided by NMR fingerprinting. Their structures, including their absolute configurations, were elucidated by spectroscopic analyses and time-dependent density-functional-theory-calculated electronic circular dichroism spectra; the data were subsequently analyzed to gain insight into the respective biogenetic relationships between the isolates, which exhibited anti-H1N1 and immunosuppressive activities.
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Metal–Ligand Cooperative Reactivity in the (Pseudo)-Dearomatized PNx(P) Systems: The Influence of the Zwitterionic Form in Dearomatized Pincer Complexes. J Am Chem Soc 2017; 139:13442-13449. [DOI: 10.1021/jacs.7b06305] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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A New Role for CO2: Controlling Agent of the Anionic Ring-Opening Polymerization of Cyclic Esters. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01425] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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21
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Benzo[4,5]cyclohepta[1,2- b]fluorene: an isomeric motif for pentacene containing linearly fused five-, six- and seven-membered rings. Chem Sci 2016; 7:6176-6181. [PMID: 30034757 PMCID: PMC6024176 DOI: 10.1039/c6sc01795a] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 06/07/2016] [Indexed: 11/21/2022] Open
Abstract
A new class of conjugated polycyclic molecules containing a C6–C5–C6–C7–C6 polycylic framework was synthesized. Both experiments and calculations show different electron structures in comparison to their pentacene isomers.
Benzo[4,5]cyclohepta[1,2-b]fluorene (5a), a new π-conjugated polycyclic hydrocarbon containing linearly fused six-, five-, six-, seven- and six-membered rings (C6–C5–C6–C7–C6), was designed and its stable derivatives 5b and 5c were synthesized. With 22 π electrons, 5a is an isomer of pentacene with quinoidal, dipolar ionic and diradical resonance forms. Molecules 5b and 5c were experimentally investigated with cyclic voltammetry, electronic absorption spectroscopy and X-ray crystallographic analysis, and theoretically studied by calculating the NICS value, diradical character and dipole moment. A comparison of 5a–c with pentacene and other pentacene analogues containing linearly fused five- or seven-membered rings was also conducted and discussed. It was found that 5b behaved as a p-type organic semiconductor in solution-processed thin film transistors with a field effect mobility of up to 0.025 cm2 V–1 s–1.
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23
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24
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Octazethrene and Its Isomer with Different Diradical Characters and Chemical Reactivity: The Role of the Bridge Structure. J Org Chem 2016; 81:2911-9. [DOI: 10.1021/acs.joc.6b00172] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Toward Tetraradicaloid: The Effect of Fusion Mode on Radical Character and Chemical Reactivity. J Am Chem Soc 2016; 138:1065-77. [DOI: 10.1021/jacs.5b12532] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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26
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Exploring Diradical Chemistry: A Carbon-Centered Radical May Act as either an Anion or Electrophile through an Orbital Isomer. Angew Chem Int Ed Engl 2015; 54:4531-4. [DOI: 10.1002/anie.201411334] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Indexed: 11/08/2022]
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27
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Exploring Diradical Chemistry: A Carbon-Centered Radical May Act as either an Anion or Electrophile through an Orbital Isomer. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201411334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Organoytterbium ate complexes extend the value of cyclobutenediones as isoprene equivalents. Angew Chem Int Ed Engl 2013; 52:13076-9. [PMID: 24155206 PMCID: PMC4285119 DOI: 10.1002/anie.201307193] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Indexed: 11/17/2022]
Abstract
Changing course: While organolithium and Grignard reagents favor addition to C1 of A (R=Me), the corresponding organoytterbium reagents add to C2 (R=tBu). Computational studies provide insights into the nature of organoytterbium species and their reactivity, and a total synthesis of (-)-mansonone B illustrates the utility of the method in terpenoid synthesis. Tf=trifluoromethanesulfonyl.
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29
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Organoytterbium Ate Complexes Extend the Value of Cyclobutenediones as Isoprene Equivalents. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201307193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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30
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An Efficient Flow-Photochemical Synthesis of 5H-Furanones Leads to an Understanding of Torquoselectivity in Cyclobutenone Rearrangements. Angew Chem Int Ed Engl 2012; 51:4405-8. [DOI: 10.1002/anie.201200281] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/06/2012] [Indexed: 11/09/2022]
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31
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An Efficient Flow-Photochemical Synthesis of 5H-Furanones Leads to an Understanding of Torquoselectivity in Cyclobutenone Rearrangements. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201200281] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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An Ammonia-Triggered Stereocontrolled Conversion of a γ-Lactone to the Central Tetrahydropyran of Pederin, Psymberin, and Onnamides D-F. European J Org Chem 2012. [DOI: 10.1002/ejoc.201101543] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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33
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New Insights into Cyclobutenone Rearrangements: A Total Synthesis of the Natural ROS-Generating Anti-Cancer Agent Cribrostatin 6. Chemistry 2011; 17:13698-705. [DOI: 10.1002/chem.201102263] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Indexed: 11/07/2022]
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