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Li YH, Chen JH, Yang Z. Exo-Selective Diels-Alder Reactions. Chemistry 2024; 30:e202304371. [PMID: 38412422 DOI: 10.1002/chem.202304371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Indexed: 02/29/2024]
Abstract
The Diels-Alder reaction stands as one of the most pivotal transformations in organic chemistry. Its efficiency, marked by the formation of two carbon-carbon bonds and up to four new stereocenters in a single step, underscores its versatility and indispensability in synthesizing natural products and pharmaceuticals. The most significant stereoselectivity feature is the "endo rule". While this rule underpins the predictability of the stereochemical outcomes, it also underscores the challenges in achieving the opposite diastereoselectivity, making the exo-Diels-Alder reactions often considered outliers. This review delves into recent examples of exo-Diels-Alder reactions, shedding light on the factors inverting the intrinsic tendency. We explore the roles of steric, electrostatic, and orbital interactions, as well as thermodynamic equilibriums in influencing exo/endo selectivity. Furthermore, we illustrate strategies to manipulate these factors, employing approaches such as bulky substituents, s-cis conformations, transient structural constraints, and innovative control physics. Through these analyses, our aim is to provide a comprehensive understanding of how to predict and design exo-Diels-Alder reactions, paving the way for new diastereoselective catalyst systems and expanding the chemical scope of Diels-Alder reactions.
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Affiliation(s)
- Yuan-He Li
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education and Beijing National Laboratory for Molecular Science (BNLMS), and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Jia-Hua Chen
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education and Beijing National Laboratory for Molecular Science (BNLMS), and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Zhen Yang
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education and Beijing National Laboratory for Molecular Science (BNLMS), and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055
- Shenzhen Bay Laboratory, Shenzhen, 518067, China
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2
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Wang J, Liu Z, Li J, Song Z, Hu C, Su Z. exo/endo Selectivity Control in Diels-Alder Reactions of Geminal Bis(silyl) Dienes: Theoretical and Experimental Studies. J Org Chem 2019; 84:3940-3952. [PMID: 30865446 DOI: 10.1021/acs.joc.8b03090] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The factors controlling the reactivity and exo/ endo selectivity of Diels-Alder reactions of geminal bis(silyl) dienes catalyzed by AlEt2Cl are studied at the B3LYP-D3(BJ)(SMD,CH2Cl2)/6-31++G**//B3LYP-D3(BJ)(SMD,CH2Cl2)/6-31+G* theoretical level. The reaction proceeds via a two-stage one-step mechanism, and the AlEt2Cl as a Lewis acid catalyst enhances the electrophilicity of the carbonyl compound by coordination, consequently accelerating a cycloaddition reaction with a low energy barrier. A geminal bis(silyl) group of the diene and an α-substituent in α,β-unsaturated carbonyl compounds adjust the interaction energy (Δ Eint) as well as the deformation energy (Δ Estrain) of the diene and dienophile, affecting the barrier height and the diastereochemical outcome accordingly. The steric repulsion between the geminal bis(silyl) group and Al(III) catalyst increases the Pauli repulsion energy (Δ EPauli) and strain energy of dienophile fragment (Δ Estrain(dienophile-LA)) in the endo pathway, ensuring the exo selectivity. The introduction of a halogen atom (Cl or Br) or methyl group at the α-position of α,β-unsaturated carbonyl compounds increases the deformation energy of the diene fragment. Meanwhile, the noncovalent interactions (that is, dispersion and electrostatic interaction) stabilize the endo transition state, leading to predominant endo products. The theoretical predictions of the exo/ endo selectivity for Diels-Alder reactions of the substituted α,β-unsaturated carbonyl compound with Cl or Br atoms by the DFT method are also well confirmed by experiment.
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Affiliation(s)
- Junming Wang
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry , Sichuan University , Chengdu 610041 , People's Republic of China
| | - Zengjin Liu
- Key Laboratory of Drug Targeting and Drug Delivery System, Ministry of Education, Department of Medicinal Chemistry, West China School of Pharmacy , Sichuan University , Chengdu 610041 , People's Republic of China
| | - Jing Li
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry , Sichuan University , Chengdu 610041 , People's Republic of China
| | - Zhenlei Song
- Key Laboratory of Drug Targeting and Drug Delivery System, Ministry of Education, Department of Medicinal Chemistry, West China School of Pharmacy , Sichuan University , Chengdu 610041 , People's Republic of China.,State Key Laboratory of Biotherapy, West China Hospital , Sichuan University , Chengdu 610041 , People's Republic of China
| | - Changwei Hu
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry , Sichuan University , Chengdu 610041 , People's Republic of China
| | - Zhishan Su
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry , Sichuan University , Chengdu 610041 , People's Republic of China
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3
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Jiang B, Liang QJ, Han Y, Zhao M, Xu YH, Loh TP. Copper-Catalyzed Dehydrogenative Diels-Alder Reaction. Org Lett 2018; 20:3215-3219. [PMID: 29790760 DOI: 10.1021/acs.orglett.8b01067] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A practical and effective copper-catalyzed dehydrogenative Diels-Alder reaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.
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Affiliation(s)
- Bing Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Qiu-Ju Liang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Yu Han
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Meng Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Yun-He Xu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Teck-Peng Loh
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry , University of Science and Technology of China , Hefei 230026 , China.,Institute of Advanced Synthesis, Jiangsu National Synergetic Innovation Center for Advanced Materials , Nanjing Tech University , Nanjing 210009 , P. R. China.,Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
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4
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Barluenga J, Aguilar E. Group 6 Metal Fischer Carbene Complexes. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2017. [DOI: 10.1016/bs.adomc.2017.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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5
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Liu Z, Lin X, Yang N, Su Z, Hu C, Xiao P, He Y, Song Z. Unique Steric Effect of Geminal Bis(silane) To Control the High Exo-selectivity in Intermolecular Diels–Alder Reaction. J Am Chem Soc 2016; 138:1877-83. [PMID: 26799581 DOI: 10.1021/jacs.5b09689] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Zengjin Liu
- Key Laboratory of Drug Targeting and Drug
Delivery System,
Ministry of Education, Department of Medicinal Chemistry, West China
School of Pharmacy, Sichuan University, Chengdu 610041, P. R. China
| | - Xinglong Lin
- Key Laboratory of Drug Targeting and Drug
Delivery System,
Ministry of Education, Department of Medicinal Chemistry, West China
School of Pharmacy, Sichuan University, Chengdu 610041, P. R. China
| | - Na Yang
- Key
Laboratory of Green Chemistry and Technology, Ministry of Education,
College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Zhishan Su
- Key
Laboratory of Green Chemistry and Technology, Ministry of Education,
College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Changwei Hu
- Key
Laboratory of Green Chemistry and Technology, Ministry of Education,
College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Peihong Xiao
- Key Laboratory of Drug Targeting and Drug
Delivery System,
Ministry of Education, Department of Medicinal Chemistry, West China
School of Pharmacy, Sichuan University, Chengdu 610041, P. R. China
| | - Yanyang He
- Key Laboratory of Drug Targeting and Drug
Delivery System,
Ministry of Education, Department of Medicinal Chemistry, West China
School of Pharmacy, Sichuan University, Chengdu 610041, P. R. China
| | - Zhenlei Song
- Key Laboratory of Drug Targeting and Drug
Delivery System,
Ministry of Education, Department of Medicinal Chemistry, West China
School of Pharmacy, Sichuan University, Chengdu 610041, P. R. China
- State
Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
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6
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García-Rodríguez J, González J, Santamaría J, Suárez-Sobrino ÁL, Rodríguez MA. Higher-order cyclization reactions of alkenyl Fischer carbene complexes: a new selective all-carbon [8 + 2] cyclization with 8-methoxyheptafulvene and computational mechanistic analysis. Dalton Trans 2016; 45:11353-61. [DOI: 10.1039/c6dt01465h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new all-carbon [8 +2] cycloaddition of alkenyl Fischer carbene complexes is described.
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Affiliation(s)
- Jaime García-Rodríguez
- Instituto Universitario de Química Organometálica “Enrique Moles” and Departamento de Química Orgánica e Inorgánica
- Universidad de Oviedo
- 33071 Oviedo
- Spain
| | - Jairo González
- Instituto Universitario de Química Organometálica “Enrique Moles” and Departamento de Química Orgánica e Inorgánica
- Universidad de Oviedo
- 33071 Oviedo
- Spain
| | - Javier Santamaría
- Instituto Universitario de Química Organometálica “Enrique Moles” and Departamento de Química Orgánica e Inorgánica
- Universidad de Oviedo
- 33071 Oviedo
- Spain
| | - Ángel L. Suárez-Sobrino
- Instituto Universitario de Química Organometálica “Enrique Moles” and Departamento de Química Orgánica e Inorgánica
- Universidad de Oviedo
- 33071 Oviedo
- Spain
| | - Miguel A. Rodríguez
- Departamento de Química
- Centro de Investigación en Síntesis Química
- Universidad de la Rioja
- 26006 Logroño
- Spain
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7
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Zhou JH, Jiang B, Meng FF, Xu YH, Loh TP. B(C6F5)3: A New Class of Strong and Bulky Lewis Acid for Exo-Selective Intermolecular Diels–Alder Reactions of Unreactive Acyclic Dienes with α,β-Enals. Org Lett 2015; 17:4432-5. [DOI: 10.1021/acs.orglett.5b02066] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jia-Hui Zhou
- Department
of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Bing Jiang
- Department
of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Fei-Fan Meng
- Department
of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Yun-He Xu
- Department
of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Teck-Peng Loh
- Department
of Chemistry, University of Science and Technology of China, Hefei 230026, China
- Division
of Chemistry and Biological Chemistry, School of Physical and Mathematical
Sciences, Nanyang Technological University, Singapore 637371
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8
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Fang LC, Hsung RP, Ma ZX, Presser WR. A highly stereoselective Diels-Alder cycloaddition of enones with chiral cyclic 2-amidodienes derived from allenamides. Org Lett 2013; 15:4842-5. [PMID: 24001055 DOI: 10.1021/ol402254p] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Lewis acid promoted Diels-Alder cycloadditions of a series of de novo chiral cyclic 2-amidodienes are described. These cyclic 2-amidodienes are derived from chiral α-allyl allenamides via a sequence of E-selective 1,3-H shift and 6π-electron pericyclic ring closure. With enones serving as effective dienophiles, these cycloadditions can be highly diastereoselective depending upon the chiral amide substituent, thereby representing a facile entry to optically enriched [2.2.2]bicyclic manifolds.
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Affiliation(s)
- Li-Chao Fang
- Division of Pharmaceutical Sciences and Department of Chemistry, University of Wisconsin , Madison, Wisconsin 53705, United States
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9
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Álvarez CM, Carrillo R, García-Rodríguez R, Miguel D. Intramolecular carboboration of carbonyl ligands to form boroxycarbenes. Chem Commun (Camb) 2012; 48:7705-7. [DOI: 10.1039/c2cc33443g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Lin Y, Crestoni ME, Fornarini S, Mayer PM. A neutralization-reionization and reactivity mass spectrometry study of the generation of neutral hydroxymethylene. JOURNAL OF MASS SPECTROMETRY : JMS 2011; 46:546-552. [PMID: 21630382 DOI: 10.1002/jms.1923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Neutral hydroxymethylene HCOH is an important intermediate in several chemical reactions; however, it is difficult to observe due to its high reactivity. In this work, neutral hydroxymethylene and formaldehyde were generated by charge exchange neutralization of their respective ionic counterparts and then were reionized and detected as positive-ion recovery signals in neutralization-reionization mass spectrometry in a magnetic sector instrument of BEE geometry. The reionized species were characterized by their subsequent collision-induced dissociation mass spectra. The transient hydroxymethylene neutral was observed to isomerize to formaldehyde with an experimental time span exceeding 13.9 µs. The vertical neutralization energy of the HCOH(+•) ion has also been assayed using charge transfer reactions between the fast ions and stationary target gases of differing ionization energy. The measured values match the result of ab initio calculations at the QCISD/6-311 + G(d,p) and CCSD(T)/6-311 + + G(3df,2p) levels of theory. Neutral hydroxymethylene was also produced by proton transfer from CH(2) OH(+) to a strong base such as pyridine, confirmed by appropriate isotopic labeling. There is a kinetic isotope effect (KIE) for H(+) versus D(+) transfer from the C atom of the hydroxymethyl cation of ∼3, consistent with a primary KIE of a nearly thermoneutral reaction.
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Affiliation(s)
- Yawei Lin
- Department of Chemistry, University of Ottawa, Marie-Curie, Ontario, Canada
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11
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Hayashi R, Feltenberger JB, Lohse AG, Walton MC, Hsung RP. An efficient and practical entry to 2-amido-dienes and 3-amido-trienes from allenamides through stereoselective 1,3-hydrogen shifts. Beilstein J Org Chem 2011; 7:410-20. [PMID: 21512601 PMCID: PMC3079123 DOI: 10.3762/bjoc.7.53] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2011] [Accepted: 03/16/2011] [Indexed: 12/16/2022] Open
Abstract
Preparations of de novo acyclic 2-amido-dienes and 3-amido-trienes through 1,3-hydrogen shifts from allenamides are described. These 1,3-hydrogen shifts could be achieved thermally or they could be promoted by the use of Brønsted acids. Under either condition, these processes are highly regioselective in favour of the α-position, and highly stereoselective in favour of the E-configuration. In addition, 6π-electron electrocyclic ring-closure could be carried out with 3-amido-trienes to afford cyclic 2-amido-dienes, and such electrocyclic ring-closure could be rendered in tandem with the 1,3-hydrogen shift.
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Affiliation(s)
- Ryuji Hayashi
- Department of Chemistry and Division of Pharmaceutical Sciences, University of Wisconsin, Madison, WI 53705
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12
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Barluenga J, García-Rodríguez J, Suárez-Sobrino Á, Tomás M. Single and Consecutive Cyclization Reactions of Alkynyl Carbene Complexes and 8-Azaheptafulvenes: Direct Access to Polycyclic Pyrrole and Indole Derivatives. Chemistry 2009; 15:8800-6. [DOI: 10.1002/chem.200901257] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Dötz KH, Stendel J. Fischer Carbene Complexes in Organic Synthesis: Metal-Assisted and Metal-Templated Reactions. Chem Rev 2009; 109:3227-74. [DOI: 10.1021/cr900034e] [Citation(s) in RCA: 284] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Karl Heinz Dötz
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany
| | - Joachim Stendel
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany
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14
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Hayashi R, Hsung RP, Feltenberger JB, Lohse AG. Regio- and stereoselective isomerizations of allenamides: synthesis of 2-amido-dienes and their tandem isomerization-electrocyclic ring-closure. Org Lett 2009; 11:2125-8. [PMID: 19371081 DOI: 10.1021/ol900647s] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A regio- and stereoselective isomerization of allenamides is described, leading to preparations of de novo 2-amido-dienes and a tandem isomerization-6pi-electron electrocyclic ring-closure.
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Affiliation(s)
- Ryuji Hayashi
- Division of Pharmaceutical Sciences and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53705, USA
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15
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Lam YH, Cheong PHY, Blasco Mata JM, Stanway SJ, Gouverneur V, Houk KN. Diels-Alder exo selectivity in terminal-substituted dienes and dienophiles: experimental discoveries and computational explanations. J Am Chem Soc 2009; 131:1947-57. [PMID: 19154113 PMCID: PMC2635921 DOI: 10.1021/ja8079548] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Diels-Alder reactions of a series of silyloxydienes and silylated dienes with acyclic alpha,beta-unsaturated ketones and N-acyloxazolidinones have been investigated. The endo/exo stereochemical outcome is strongly influenced by the substitution pattern of the reactants. High exo selectivity was observed when the termini of the diene and the dienophile involved in the shorter of the forming bonds were both substituted, while the normal endo preference was found otherwise. The exo-selective asymmetric Diels-Alder reactions using Evans' oxazolidinone chiral auxiliary furnished a high level of pi-facial selectivity in the same sense as their well-documented endo-selective counterparts. Computational results for these Diels-Alder reactions were consistent with the experimental endo/exo selectivity in most cases. A twist-asynchronous model accounts for the geometries and energies of the computed transition structures.
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Affiliation(s)
- Yu-hong Lam
- Chemistry Research Laboratory, University of Oxford, UK
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16
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Barluenga J, García-Rodríguez J, Martínez S, Suárez-Sobrino Á, Tomás M. [8+2] and [8+3] Cyclization Reactions of Alkenyl Carbenes and 8-Azaheptafulvenes: Direct Access to Tetrahydro-1-azaazulene and Cyclohepta[b]pyridinone Derivatives. Chem Asian J 2008; 3:767-75. [DOI: 10.1002/asia.200700340] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Aznar F, Fañanás-Mastral M, Alonso J, Fañanás FJ. Diastereoselective Synthesis of Three-, Five-, Six-, and Seven-Membered Rings from Fischer Carbene Complexes and 4-Unsubstituted 1-Amino-1,3-Dienes. Chemistry 2007; 14:325-32. [PMID: 17886851 DOI: 10.1002/chem.200701109] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Fischer carbene complexes react with 4-unsubstituted 1-amino-1,3-dienes to give different carbocyclization products depending on the nature of the carbene complex and on the substitution pattern of the aminodiene. Thus, the reaction of arylcarbene chromium complexes and 1-aminodienes diastereoselectively affords cyclopropane derivatives by means of a formal [2+1] carbocyclization reaction. In particular, pentacarbonyl[(2-furyl)(methoxy)methylene]chromium complex furnishes formal [4+1] carbocyclization products. Starting from beta-substituted alkenylcarbene complexes, formal [4+1] reactions occur and cyclopentenamine derivatives are diastereoselectively formed. However, when the alpha,beta-disubstituted alkenylcarbene complex pentacarbonyl[(5,6-dihydro-2H-pyran-2-yl)(methoxy)methylene]tungsten is used, the outcome of the reaction depends on the substitution on the carbon atom at the 3-position of the aminodiene, generating the [3+2] or [4+3]-cyclization products if the substituent is or is not a hydrogen atom, respectively. Finally, when the reaction is performed with alkynylcarbene complexes, benzaldehyde derivatives are obtained if the triple-bond substituent is a phenyl group or indene derivatives if the group is an alkenyl moiety.
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Affiliation(s)
- Fernando Aznar
- Instituto Universitario de Química Organometálica, Enrique Moles, Unidad Asociada al CSIC, Universidad de Oviedo, Julián Clavería 8, 33006 Oviedo, Spain.
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18
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Barluenga J, García-Rodríguez J, Martínez S, Suárez-Sobrino AL, Tomás M. Facile and Versatile Annulation of the Imidazole Ring: Single and Sequential Cyclization Reactions of Fischer Carbene Complexes with 1,4-Diazafulvenes. Chemistry 2006; 12:3201-10. [PMID: 16506252 DOI: 10.1002/chem.200501402] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We examined the reactivity of dimethylaminodiazafulvene 1 toward Fischer alkenylcarbene 2 and alkynylcarbene 3 complexes. Diazafulvene 1 reacts with alkenylcarbenes 2 through a formal [6+3] heterocyclization in a regio- and stereoselective manner to afford dihydroimidazo[1,2-a]pyridines 4. Acid-promoted dimethylamine elimination in compound 4 c gives rise to the aromatic imidazo pyridine 5. A likely mechanism for this reaction is a 1,2-nucleophilic addition/[1,2]-shift metal-promoted cyclization sequence. On the other hand, diazafulvene 1 and alkynyl carbenes 3 undergo a [6+2] cyclization to afford pyrrolo[1,2-a]imidazole carbene complex 6 that can be readily oxidized to the corresponding esters 7. When enynylcarbenes 3 e-i are treated with diazafulvene 1, consecutive and diastereoselective [6+2]/cyclopentannulation cyclization reactions take place affording new polycyclic complex systems 8, 9, and 12 that can be appropriately demetallated to the corresponding imidazole-based polyfused systems 10, 11, and 13 respectively. Finally, enynylcarbenes 3 d,f undergo consecutive [6+2]/[5+1] cyclization reactions with diazafulvene 1 and tBuNC, respectively, to yield tetracyclic adducts 14 and 15. All these processes result in high yields and provide a route to the preparation of imidazopyridines and pyrroloimidazoles as well as other polycyclic molecules that contain imidazole groups, which are interesting from a pharmacological and biological point of view.
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Affiliation(s)
- José Barluenga
- Instituto Universitario de Química Organometálica Enrique Moles, Unidad Asociada al CSIC Universidad de Oviedo, Julián Clavería 8, 33006 Oviedo, Spain.
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19
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Barluenga J, Martínez S, Suárez-Sobrino AL, Tomás M. Versatile Reactivity of Alkynyl Fischer Carbene Complexes toward Pentafulvenes: Carbocyclization and C−H Insertion Reactions. Organometallics 2006. [DOI: 10.1021/om0601394] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- José Barluenga
- Instituto Universitario de Química Organometálica “Enrique Moles” Unidad Asociada al CSIC, Universidad de Oviedo, Julian Clavería 8 33071 Oviedo, Spain
| | - Silvia Martínez
- Instituto Universitario de Química Organometálica “Enrique Moles” Unidad Asociada al CSIC, Universidad de Oviedo, Julian Clavería 8 33071 Oviedo, Spain
| | - Angel L. Suárez-Sobrino
- Instituto Universitario de Química Organometálica “Enrique Moles” Unidad Asociada al CSIC, Universidad de Oviedo, Julian Clavería 8 33071 Oviedo, Spain
| | - Miguel Tomás
- Instituto Universitario de Química Organometálica “Enrique Moles” Unidad Asociada al CSIC, Universidad de Oviedo, Julian Clavería 8 33071 Oviedo, Spain
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Barluenga J, Fernández MA, Aznar F, Valdés C. Palladium-Catalyzed Cross-Coupling Reactions of Amines with Alkenyl Bromides: A New Method for the Synthesis of Enamines and Imines. Chemistry 2004; 10:494-507. [PMID: 14735518 DOI: 10.1002/chem.200305406] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The palladium-catalyzed cross-coupling reaction of alkenyl bromides with secondary and primary amines gives rise to enamines and imines, respectively. This new transformation expands the applicability of palladium-catalyzed C-N bond forming reactions (the Buchwald-Hartwig amination), which have mostly been applied to aryl halides. After screening of different ligands, bases, and solvents, the catalytic combination [Pd(2)(dba)(3)]/BINAP in the presence of NaOtBu in toluene gave the best results in the cross-coupling of secondary amines with 1-bromostyrene (dba=dibenzylideneacetone, BINAP=2,2'-bis(diphenylphosphino)-1,1'-binaphthyl). The corresponding enamines are obtained cleanly and in nearly quantitative yields. However, steric hindrance seems to be a limitation of the reaction, as amines carrying large substituents are not well converted. The same methodology can be applied to the coupling of secondary amines with 2-bromostyrene. Moreover, the reaction with substituted 2-bromopropenes allows regioselective synthesis of isomerizable terminal enamines without isomerization of the double bond. The best catalytic conditions for the cross-coupling of 1-bromostyrene with primary amines include again the use of the Pd(0)/BINAP/NaOtBu system. The reaction gives rise to the expected imines in very short times and with low catalyst loadings. A set of structurally diverse imines can be prepared by this methodology through variations in the structure of both coupling partners. However, 2-bromostyrene failed to give good results in this coupling reaction, probably due to product inhibition of the catalytic cycle. Competition experiments of vinyl versus aryl amination reveal that the reaction occurs preferentially on vinyl bromides.
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Affiliation(s)
- José Barluenga
- Instituto Universitario de Química Organometálica Enrique Moles, Universidad de Oviedo, 33071 Oviedo, Spain.
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21
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Boren B, Hirschi JS, Reibenspies JH, Tallant MD, Singleton DA, Sulikowski GA. Exo-Selective Diels−Alder Reactions of Vinylazepines. Origin of Divergent Stereoselectivity in Diels−Alder Reactions of Vinylazepines, Vinylpiperideines, and Vinylcycloalkenes. J Org Chem 2003; 68:8991-5. [PMID: 14604372 DOI: 10.1021/jo034462h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Diels-Alder reactions of vinylazepines with N-phenylmaleimide afforded exclusively the exo cycloadduct, while high endo stereoselectivity was observed, as previously reported, in analogous reactions of vinylpiperideines. This curious contrast was confirmed by X-ray analysis of cycloadducts not susceptible to epimerization. The stereoselectivity of Diels-Alder reactions of vinylazepines, vinylpiperideines, and vinylcycloalkenes exhibits surprising divergence depending on the detailed diene structure, and DFT calculations (Becke3LYP) were undertaken to shed light on these observations. The model calculations correctly predict the major stereoisomers in these reactions, though they tend to significantly underestimate the stereoselectivity. The results suggest some general considerations in predicting or controlling the stereochemistry of this class of Diels-Alder reactions.
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Affiliation(s)
- Brant Boren
- Department of Chemistry, Texas A&M University, College Station, TX 77842, USA
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22
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Barluenga J, López S, Trabanco AA, Flórez J. 2- and 3-haloalkoxy fischer carbene complexes of chromium as synthons for either hydroxycyclopropanation or oxaspirocyclopropanation of alkenes. Chemistry 2001; 7:4723-9. [PMID: 11757665 DOI: 10.1002/1521-3765(20011105)7:21<4723::aid-chem4723>3.0.co;2-v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The thermal reaction of 2-haloethoxy- and 3-chloropropoxy(alkenyl)carbene complexes of chromium with electronically neutral alkenes furnished diastereoselectively the corresponding 1-haloalkoxy-l-vinylcyclopropanes that, subjected to subsequent halogen-lithium exchange reactions, provided vinylcyclopropanols or compounds containing the spiro[cyclopropane-tetrahydrofuran/tetrahydropyran] structure, depending on the nature of both the halogen atom and the lithiating reagent. The hydroxycyclopropanation reaction can be efficiently achieved in a one-pot fashion.
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Affiliation(s)
- J Barluenga
- Instituto Universitario de Química Organometálica Enrique Moles Unidad Asociada al CSIC, Universidad de Oviedo Spain.
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Chapman J, Day C, Welker M. Enantioselective Diels−Alder Reactions of Optically Active (Buta-1,3-dien-2-yl)(salen)cobalt(III) Complexes. European J Org Chem 2001. [DOI: 10.1002/1099-0690(200106)2001:12<2273::aid-ejoc2273>3.0.co;2-i] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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Herndon JW. The chemistry of the carbon–transition metal double and triple bond: annual survey covering the year 1998. Coord Chem Rev 2000. [DOI: 10.1016/s0010-8545(99)00234-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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25
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Sierra MA. Di- and polymetallic heteroatom stabilized (Fischer) metal carbene complexes. Chem Rev 2000; 100:3591-638. [PMID: 11749323 DOI: 10.1021/cr9804137] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M A Sierra
- Departamento de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain
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26
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Hegedus LS. Transition metals in organic synthesis: highlights for the year 1998 (25th Anniversary). Coord Chem Rev 2000. [DOI: 10.1016/s0010-8545(99)00172-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Barluenga J, Fernández-Marí F, González R, Aguilar E, Revelli G, Viado A, Fañanás F, Olano B. α,β-Unsaturated Fischer Carbene Complexes vs. 1,3-Dipoles: Reactions with Nitrones and Nitrilimines. European J Org Chem 2000. [DOI: 10.1002/(sici)1099-0690(200005)2000:9<1773::aid-ejoc1773>3.0.co;2-e] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Chapman JJ, Day CS, Welker ME. Synthesis and Enantioselective Diels−Alder Reactions of Optically Active Cobalt(III) Salen-1,3-butadien-2-yl Complexes. Organometallics 2000. [DOI: 10.1021/om000074j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- John J. Chapman
- Department of Chemistry, Wake Forest University, Post Office Box 7486, Winston-Salem, North Carolina 27109, and Lorillard Research Center, 420 English Street, Greensboro, North Carolina 27420-1688
| | - Cynthia S. Day
- Department of Chemistry, Wake Forest University, Post Office Box 7486, Winston-Salem, North Carolina 27109, and Lorillard Research Center, 420 English Street, Greensboro, North Carolina 27420-1688
| | - Mark E. Welker
- Department of Chemistry, Wake Forest University, Post Office Box 7486, Winston-Salem, North Carolina 27109, and Lorillard Research Center, 420 English Street, Greensboro, North Carolina 27420-1688
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Kozmin SA, Rawal VH. Chiral Amino Siloxy Dienes in the Diels−Alder Reaction: Applications to the Asymmetric Synthesis of 4-Substituted and 4,5-Disubstituted Cyclohexenones and the Total Synthesis of (−)-α-Elemene. J Am Chem Soc 1999. [DOI: 10.1021/ja9921930] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sergey A. Kozmin
- Contribution from the Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
| | - Viresh H. Rawal
- Contribution from the Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
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30
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Richardson B, Day CS, Welker ME. Transition-metal mediated exo selective and enantioselective Diels–Alder reactions for the preparation of octalones with unusual stereochemistries. Reactions of 2-cobaloxime substituted 1,3-dienes with cyclohexenone in optically active Lewis acid catalyzed [4+2] cycloadditions. J Organomet Chem 1999. [DOI: 10.1016/s0022-328x(98)01036-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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