1
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Lukoyanov AA, Tabolin AA, Nelyubina YV, Aksenova SA, Sukhorukov AY. Nitronate-aryne cycloaddition as a concise route to stereochemically complex fused benzisoxazolines and amino alcohols. Org Biomol Chem 2023; 21:3871-3880. [PMID: 37097315 DOI: 10.1039/d3ob00235g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
The reaction of cyclic nitronates (isoxazoline N-oxides and 5,6-dihydro-4H-1,2-oxazine N-oxides) with Kobayashi's aryne precursors affords tricyclic benzene-fused nitroso acetals as a result of [3 + 2]-cycloaddition. The process is regio- and stereoselective in most cases and produces the target cycloadducts possessing up to four contiguous stereogenic centers. These nitroso acetals were shown to be convenient precursors of valuable polysubstituted aminodiols through catalytic hydrogenolysis of the N-O bonds. Also, the action of protic acids resulted in an unusual fragmentation of the cyclic nitroso acetal moiety through heterolytic N-O bond cleavage and Beckmann-type reaction. Using this acid-mediated reaction, the synthesis of a hitherto unknown hexahydrobenzo[4,5]isoxazolo[2,3-a]azepine scaffold was accomplished.
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Affiliation(s)
- Alexander A Lukoyanov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation.
| | - Andrey A Tabolin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation.
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds, 119991, Vavilov str. 28, Moscow, Russian Federation
| | - Svetlana A Aksenova
- A. N. Nesmeyanov Institute of Organoelement Compounds, 119991, Vavilov str. 28, Moscow, Russian Federation
- Moscow Institute of Physics and Technology (National Research University), 141700, Institutskiy per. 9, Dolgoprudny, Moscow Region, Russian Federation
| | - Alexey Yu Sukhorukov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation.
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2
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Donkor B, Umar AR, Opoku E. Mechanistic elucidation of the tandem Diels–Alder/(3 + 2) cycloadditions in the design and syntheses of heterosteroids. J Mol Model 2022; 28:70. [DOI: 10.1007/s00894-022-05063-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/16/2022] [Indexed: 11/28/2022]
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3
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Umar AR, Opoku E. Mechanistic studies on stereoselective domino [4 + 2]/retro[3 + 2]/[3 + 2] cycloaddition reactions of oxadiazoles with strained and unstrained cycloalkenes. Theor Chem Acc 2022. [DOI: 10.1007/s00214-022-02872-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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4
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Malykhin RS, Golovanov IS, Nelyubina YV, Ioffe SL, Sukhorukov AY. Construction of Saturated Oxazolo[3,2- b][1,2]oxazines via Tandem [3+2]-Cycloaddition/[1,3]-Rearrangement of Cyclic Nitronates and Ketenes. J Org Chem 2021; 86:16337-16348. [PMID: 34783561 DOI: 10.1021/acs.joc.1c01744] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction of six-membered cyclic nitronates with disubstituted ketenes affords hitherto unknown saturated oxazolo[3,2-b][1,2]oxazines possessing up to four contiguous stereogenic centers. The process involves a tandem of [3+2]-cycloaddition across the C═O bond of ketene, followed by a spontaneous [1,3]-rearrangement of transient vinylidene-substituted bicyclic nitrosoacetals. DFT calculations of the mechanism suggest that the [1,3]-O,C-shift proceeds through a recyclization of a biradical intermediate formed by an unusually mild homolytic cleavage of the N-O bond. The resulting products can be utilized as precursors of other fused 1,2-oxazines derivatives, in particular 1,2-oxazino-1,2,4-triazin-3-ones.
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Affiliation(s)
- Roman S Malykhin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation.,Department of Chemistry, M. V. Lomonosov Moscow State University, 119991, Leninskie gory, 1, str. 3, Moscow, Russian Federation
| | - Ivan S Golovanov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds, 119991, Vavilov str. 28, Moscow, Russian Federation
| | - Sema L Ioffe
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation
| | - Alexey Yu Sukhorukov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation
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5
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Opoku E, Baffour Pipim G, Tia R, Adei E. Mechanistic study of the tandem intramolecular (4 + 2)/intermolecular (3 + 2) cycloaddition reactions for the formation of polyaza‐ and polyisoxazolidine‐steroids. J Heterocycl Chem 2020. [DOI: 10.1002/jhet.3900] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Ernest Opoku
- Theoretical and Computational Chemistry Laboratory, Department of ChemistryKwame Nkrumah University of Science and Technology Kumasi Ghana
| | - George Baffour Pipim
- Theoretical and Computational Chemistry Laboratory, Department of ChemistryKwame Nkrumah University of Science and Technology Kumasi Ghana
| | - Richard Tia
- Theoretical and Computational Chemistry Laboratory, Department of ChemistryKwame Nkrumah University of Science and Technology Kumasi Ghana
| | - Evans Adei
- Theoretical and Computational Chemistry Laboratory, Department of ChemistryKwame Nkrumah University of Science and Technology Kumasi Ghana
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6
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Gudmundsson HG, Kuper CJ, Cornut D, Urbitsch F, Elbert BL, Anderson EA. Synthesis of Cyclic Alkenyl Dimethylsiloxanes from Alkynyl Benzyldimethylsilanes and Application in Polyene Synthesis. J Org Chem 2019; 84:14868-14882. [PMID: 31646859 DOI: 10.1021/acs.joc.9b01664] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclic dimethylalkenylsiloxanes, useful motifs for (Z)-selective Hiyama cross-coupling, are accessed from alkynyl benzyldimethylsilanes featuring adjacent allylic or homoallylic oxygen substituents by semihydrogenation/debenzylation/cyclization. While formation of 5- and 6-membered rings can be achieved from the free alcohols using fluoride or silanolate, allylic acetate precursors to 5-membered rings display distinct modes of activation. The utility of these compounds is demonstrated through the preparation of a variety of (Z)-alkene-containing polyenes and application to a concise total synthesis of leukotriene B3.
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Affiliation(s)
| | - Christian J Kuper
- Chemistry Research Laboratory , 12 Mansfield Road , Oxford OX1 3TA , U.K
| | - Damien Cornut
- Chemistry Research Laboratory , 12 Mansfield Road , Oxford OX1 3TA , U.K
| | - Felix Urbitsch
- Chemistry Research Laboratory , 12 Mansfield Road , Oxford OX1 3TA , U.K
| | - Bryony L Elbert
- Chemistry Research Laboratory , 12 Mansfield Road , Oxford OX1 3TA , U.K
| | - Edward A Anderson
- Chemistry Research Laboratory , 12 Mansfield Road , Oxford OX1 3TA , U.K
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7
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Motornov VA, Tabolin AA, Novikov RA, Nelyubina YV, Nenajdenko VG, Ioffe SL. Fluoronitroalkenes in tandem [4 + 1]/[3 + 2]-cycloaddition: one-pot three-component assembly of fluorinated bicyclic nitroso acetals. Org Chem Front 2018. [DOI: 10.1039/c8qo00623g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Novel fluorinated bicyclic nitroso acetals were obtained in a highly regio- and diastereo-selective manner via tandem [4 + 1]/[3 + 2]-cycloaddition of fluoronitroalkenes.
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Affiliation(s)
- Vladimir A. Motornov
- N. D. Zelinsky Institute of Organic Chemistry
- Russian Academy of Sciences
- Moscow
- Russia
- Higher Chemical College
| | - Andrey A. Tabolin
- N. D. Zelinsky Institute of Organic Chemistry
- Russian Academy of Sciences
- Moscow
- Russia
| | - Roman A. Novikov
- N. D. Zelinsky Institute of Organic Chemistry
- Russian Academy of Sciences
- Moscow
- Russia
- V. A. Engelhardt Institute of Molecular Biology
| | - Yulia V. Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Moscow
- Russia
| | | | - Sema L. Ioffe
- N. D. Zelinsky Institute of Organic Chemistry
- Russian Academy of Sciences
- Moscow
- Russia
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8
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Halimehjani AZ, Namboothiri INN, Hooshmand SE. Part I: Nitroalkenes in the synthesis of heterocyclic compounds. RSC Adv 2014. [DOI: 10.1039/c4ra08828j] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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9
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Cleary L, Pitzen J, Brailsford JA, Shea KJ. Progress toward the total synthesis of N-methylwelwitindolinone B isothiocyanate. Org Lett 2014; 16:4460-3. [PMID: 25124334 DOI: 10.1021/ol5020043] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Progress toward the welwitindolinone alkaloid N-methylwelwitindolinone B isothiocyanate is reported. A key reaction to synthesize the [4.3.1] bicycle embedded in the core of the molecule is a furan type 2 intramolecular Diels-Alder reaction with a tetrasubstituted dienophile, which sets the two vicinal quaternary centers present in the natural product. The sterically encumbered cycloaddition precursor was synthesized using a Horner-Wadsworth-Emmons reaction followed by a Suzuki cross-coupling reaction. Finally, introduction of the secondary alkyl chloride was achieved by a regio- and diastereoselective opening of a [2.2.1] oxobicycloheptane functionality.
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Affiliation(s)
- Leah Cleary
- Department of Chemistry, University of California, Irvine , 1102 Natural Sciences 2, Irvine, California 92697-2025, United States
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10
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Wade PA, Pipic A, Zeller M, Tsetsakos P. Sequential Diels-Alder/[3,3]-sigmatropic rearrangement reactions of β-nitrostyrene with 3-methyl-1,3-pentadiene. Beilstein J Org Chem 2013; 9:2137-46. [PMID: 24204426 PMCID: PMC3817504 DOI: 10.3762/bjoc.9.251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 09/21/2013] [Indexed: 11/30/2022] Open
Abstract
The tin(IV)-catalyzed reaction of β-nitrostyrene with (E)-3-methyl-1,3-pentadiene in toluene afforded two major nitronic ester cycloadducts in 27% and 29% yield that arise from the reaction at the less substituted diene double bond. Also present were four cycloadducts from the reaction at the higher substituted diene double bond, two of which were the formal cycloadducts of (Z)-3-methyl-1,3-pentadiene. A Friedel–Crafts alkylation product from the reaction of the diene, β-nitrostyrene, and toluene was also obtained in 10% yield. The tin(IV)-catalyzed reaction of β-nitrostyrene with (Z)-3-methyl-1,3-pentadiene in dichloromethane afforded four nitronic ester cycloadducts all derived from the reaction at the higher substituted double bond. One cycloadduct was isolated in 45% yield and two others are formal adducts of the E-isomer of the diene. The product formation in these reactions is consistent with a stepwise mechanism involving a zwitterionic intermediate. The initially isolated nitronic ester cycloadducts underwent tin(IV)-catalyzed interconversion, presumably via zwitterion intermediates. Cycloadducts derived from the reaction at the less substituted double bond of (E)-3-methyl-1,3-pentadiene underwent a [3,3]-sigmatropic rearrangement on heating to afford 4-nitrocyclohexenes. Cycloadducts derived from the reaction at the higher substituted diene double bond of either diene failed to undergo a thermal rearrangement. Rates and success of the rearrangement are consistent with a concerted mechanism possessing a dipolar transition state. An initial assessment of substituent effects on the rearrangement process is presented.
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Affiliation(s)
- Peter A Wade
- Department of Chemistry, Drexel University, Philadelphia, PA 19104, U.S.A
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11
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Gérard H, Chataigner I. Selectivities of Multicomponent [4 + 2]/[3 + 2] Cycloadditions of 3-Nitroindole with Substituted Alkenes: A DFT Analysis. J Org Chem 2013; 78:9233-42. [DOI: 10.1021/jo401482b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Hélène Gérard
- Laboratoire de Chimie Théorique
UMR 7616, UPMC Univ Paris 06, F-75005 Paris,
France
| | - Isabelle Chataigner
- Laboratoire COBRA, CNRS UMR 6014 & FR 3038, Université de Rouen, 76821 Mont St Aignan, France
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12
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de Carvalho LL, Burrow RA, Pereira VLP. Diastereoselective synthesis of nitroso acetals from (S,E)-γ-aminated nitroalkenes via multicomponent [4 + 2]/[3 + 2] cycloadditions promoted by LiCl or LiClO4. Beilstein J Org Chem 2013; 9:838-45. [PMID: 23766798 PMCID: PMC3678848 DOI: 10.3762/bjoc.9.96] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 04/08/2013] [Indexed: 11/23/2022] Open
Abstract
Chiral nonracemic aminated nitroso acetals were synthesized via diastereoselective multicomponent [4 + 2]/[3 + 2] cycloadditions employing new (S,E)-γ-nitrogenated nitroalkenes 5a–c as heterodienes, ethyl vinyl ether (EVE) as a dienophile, and selected electron-deficient alkenes as 1,3-dipolarophiles. The employment of different organic solutions of LiClO4 or LiCl as promoter systems provided the respective nitroso acetals with yields from 34–72% and good levels of diastereoselectivity. In addition, the nitroso acetal 9c was transformed to the pyrrolizidin-3-one derivative 14c, proving the usefulness of the route in the synthesis of an interesting chiral compound. The elucidation of the stereostructures was based on 2D COSY, NOESY and HSQC NMR experiments as well as an X-ray diffraction experiment.
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Affiliation(s)
- Leandro Lara de Carvalho
- Núcleo de Pesquisas de Produtos Naturais, Laboratório de Síntese Estereosseletiva de Substâncias Bioativas, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil
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13
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Rajalakshmi P, Srinivasan N, Krishnakumar RV, Razak IA, Rosli MM. Supramolecular networks in (9-fluoro-4 H-chromeno[4,3- c]isoxazol-3-yl)methanol and its 9-chloro analogue at 100 K. Acta Crystallogr C 2012; 68:o288-93. [DOI: 10.1107/s0108270112025620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 06/05/2012] [Indexed: 11/10/2022] Open
Abstract
The title compounds, (9-fluoro-4H-chromeno[4,3-c]isoxazol-3-yl)methanol, C11H8FNO3, (I), and (9-chloro-4H-chromeno[4,3-c]isoxazol-3-yl)methanol, C11H8ClNO3, (II), crystallize in the orthorhombic space groupPbcawithZ′ = 1 and the triclinic space groupP\overline{1} withZ′ = 6, respectively. The simple replacement of F by Cl in the main molecular scaffold of (I) and (II) results in significant differences in the intermolecular interaction patterns and a corresponding change in the point-group symmetry fromD2htoCi=S2. These striking differences are manifested through the presence of C—H...F and the absence of O—H...O and C—H...O interactions in (I), and the absence of C—H...Cl and the presence of O—H...O and C—H...O interactions in (II). However, the geometry of the synthons formed by the O—H...N and O—H...X(X= F or Cl) interactions observed in the constitution of the supramolecular networks of both (I) and (II) remains similar. Also, C—H...O interactions are not preferred in the presence of F in (I), while they are much preferred in the presence of Cl in (II).
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14
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Amine nucleophilic addition to nitroalkene as a new practical approach for the synthesis of fully substituted isoxazoline-N-oxide. Tetrahedron 2011. [DOI: 10.1016/j.tet.2011.01.085] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Zhong C, Gautam L, Petersen J, Akhmedov N, Shi X. Concise Asymmetric Synthesis of Fully Substituted Isoxazoline-N-Oxide through Lewis Base Catalyzed Nitroalkene Activation. Chemistry 2010; 16:8605-9. [DOI: 10.1002/chem.201001237] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Duan H, Sun X, Liao W, Petersen JL, Shi X. Proline as Lewis Base Catalyst: Diastereoselective Synthesis of Isoxazoline-N-oxide through [3 + 2] Cycloaddition. Org Lett 2008; 10:4113-6. [PMID: 18722449 DOI: 10.1021/ol801656y] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Haifeng Duan
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Xiaohua Sun
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Wenyan Liao
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Xiaodong Shi
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506
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17
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Jiao P, Nakashima D, Yamamoto H. Enantioselective 1,3-Dipolar Cycloaddition of Nitrones with Ethyl Vinyl Ether: The Difference between Brønsted and Lewis Acid Catalysis. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705314] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Jiao P, Nakashima D, Yamamoto H. Enantioselective 1,3-Dipolar Cycloaddition of Nitrones with Ethyl Vinyl Ether: The Difference between Brønsted and Lewis Acid Catalysis. Angew Chem Int Ed Engl 2008; 47:2411-3. [DOI: 10.1002/anie.200705314] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Bruvoll M, Hansen T, Uggerud E. Organocatalysis: quantum chemical modeling of nucleophilic addition to α,β-unsaturated carbonyl compounds. J PHYS ORG CHEM 2007. [DOI: 10.1002/poc.1170] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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20
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Imhof W, Anders E. Regioselectivity in Iron-Catalyzed [2+2+1] Cycloadditions: A DFT Investigation of Substituent Effects in 1,4-Diazabutadienes. Chemistry 2004; 10:5717-29. [PMID: 15472944 DOI: 10.1002/chem.200400215] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The transition-metal-catalyzed [2+2+1] cycloaddition reaction of 1,4-diazabutadienes, in which the imine-carbon atoms are part of an oxazine ring system, with ethylene and carbon monoxide leads to the regioselective formation of pyrrolidinone derivatives. To explain this regioselectivity, the transition states and intermediates of the rate-determining step of the catalysis are determined by high-level DFT calculations. The experimentally observed regioselectivity is consistent with the lower activation energy of the addition of ethylene towards the carbon atom next to the oxazine oxygen atom. Furthermore, the activation barrier of a conceivable back reaction is higher for the intermediates with the experimentally observed regioselectivity. These thermodynamic and kinetic arguments at first sight appear to be confirmed by the calculated NPA charges in the transition states, which reveal that the differences in these charges are greatest for those transition states that lead to the formation of the energetically favored transition structures. Nevertheless, calculations of analogous transition structures and reaction products starting from 1,4-diazabutadienes with a 2-fluoro, 2-hydroxo or 2-amino substituent revealed that the regioselectivity is not determined by the electronegativity of the heteroatom and thus by the differences in the NPA charges or the resulting Coulombic interactions in the transition structures. The main reason for the observed regioselectivities is the pi-donor ability of the substituent to contribute to a delocalized pi system incorporating the adjacent imine moiety. The increasing pi-donor capability results in decreased reactivity of this moiety and increases the (relative) reactivity of the second imine group. This effect can even overcompensate for strong intramolecular Coulombic attractions in the transition structures.
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Affiliation(s)
- Wolfgang Imhof
- Institute of Inorganic and Analytical Chemistry of the Friedrich-Schiller-University Jena, August-Bebel-Strasse 2, 07743 Jena, Germany.
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21
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Denmark SE, Gomez L. Tandem double intramolecular [4+2]/[3+2] cycloadditions of nitroalkenes. The fused/bridged mode. J Org Chem 2004; 68:8015-24. [PMID: 14535778 DOI: 10.1021/jo034853w] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new class of tandem [4+2]/[3+2] cycloadditions of nitroalkenes is described in which both pericyclic processes are intramolecular. Two subclasses of intra [4+2]/intra [3+2] cycloadditions have been explored in which the dipolarophile is tethered at either C(5) or C(6) of the nitronate. For both families of precursors, the cycloadditions occur in good yield and are found to be highly regio- and stereoselective. This method converts linear polyenes to functionalized polycyclic systems bearing up to six stereogenic centers.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
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22
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Jones RS, Sutherland J, Weaver DF. Synthesis of 4-Ethoxycarbonyl-5-arylisoxazolidines via Regioselective Cycloaddition. SYNTHETIC COMMUN 2003. [DOI: 10.1081/scc-120015557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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23
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Abstract
A highly efficient total synthesis of (+)-1-epiaustraline ((+)-1), a tetrahydroxypyrrolizidine alkaloid of the alexine/australine subclass, is described. The key step is a tandem intramolecular [4 + 2]/intermolecular [3 + 2] nitroalkene cycloaddition involving dienylsilyloxy nitroalkene 3 and chiral vinyl ether 4, which establishes four of the five stereocenters present. The final center was installed by a diastereoselective dihydroxylation. Hydrogenolytic unmasking of the nitroso acetal tosylate 17 containing the silyl ether linkage was thwarted by a slow alkylation and an undesired Peterson-type elimination. Prior removal of the silicon moiety by Tamao-Fleming oxidation proceeded in excellent yield and provided a substrate suitable for hydrogenolysis and deprotection. The complete synthesis required only 10 steps to deliver the (+)-1-epiaustraline in 7.0% overall yield.
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Affiliation(s)
- S E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
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24
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Giomi D, Turchi S, Danesi A, Faggi C. 4-Nitroisoxazoles as nitroalkene heterodienes: diastereoselective synthesis of spiro tricyclic nitroso acetals by thermal reactions with ethyl vinyl ether. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00310-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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25
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Baranski A. Substituent effect on the [2?+?3] cycloaddition of (E)-?-Nitrostyrene with (Z)-C,N-Diarylnitrones. J PHYS ORG CHEM 2001. [DOI: 10.1002/poc.451] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Abstract
The first synthesis of (+)-casuarine ((+)-6), a pentahydroxy pyrrolizidine alkaloid of the alexine/australine subclass, is described. The key step is a tandem [4 + 2]/[3 + 2] nitroalkene cycloaddition involving nitrobenzoate 13, chiral vinyl ether 16c, and vinyl silane 10, which establishes five of the six stereocenters present in this potent glycosidase inhibitor. The completion of the synthesis requires only four additional steps to deliver the final product in 20% overall yield.
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Affiliation(s)
- S E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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27
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Abstract
Highly efficient and selective syntheses of the title compounds are described. The cornerstone of the synthetic plan is the tandem inter [4 + 2]/inter [3 + 2] cycloaddition process. These syntheses differ from previous applications of this strategy in that they incorporate an alkylation in the hydrogenolysis step to close the second ring of the azabicyclic systems. Notable features of the sequence are (1) the highly regio- and stereoselective [3 + 2] cycloaddition of nitronate 15 with siloxymethyl (Z)-beta-silylvinyl ketone (Z)-22b and (2) the highly selective reduction of the resulting ketone 24a with L-Selectride. A single-crystal X-ray structure analysis of synthetic (-)-7-epiaustraline confirmed that the targeted structure was successfully synthesized. This stimulated a reexamination of the structural assignment of the natural product. (-)-1-Epicastanospermine was synthesized in four steps from the common intermediate 27a. The absolute configuration of (-)-1-epicastanospermine was assured by single-crystal X-ray structure analysis of intermediate (-)-27a. Thus, the sign of the optical rotation had to be revised. The overall efficiency of these syntheses were 9 steps and 23% yield for (-)-7-epiaustraline and 10 steps and 20% yield for (-)-1-epicastanospermine
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Affiliation(s)
- S E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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28
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Abstract
[formula: see text] The first synthesis of (+)-casuarine, a pentahydroxy pyrrolizidine alkaloid, is described. The key bond-forming events occur in a tandem [4 + 2]/[3 + 2] nitroalkene cycloaddition involving nitroalkene 6, chiral vinyl ether 7b, and vinyl silane 4. This process also creates five of the six stereocenters present in this potent glycosidase inhibitor. Completion of the synthesis required only four additional steps and delivered (+)-casuarine in 20% overall yield.
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Affiliation(s)
- S E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana 61801, USA.
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