1
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Zhou J, Meng L, Yang Z, Wang JJ. Enantio- and Regioselective Cascade Hydroboration of Methylenecyclopropanes for Facile Access to Chiral 1,3- and 1,4-Bis(boronates). ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400096. [PMID: 38477439 DOI: 10.1002/advs.202400096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/06/2024] [Indexed: 03/14/2024]
Abstract
Chiral 1, n-bis(boronate) plays a crucial role in organic synthesis and medicinal chemistry. However, their catalytic and asymmetric synthesis has long posed a challenge in terms of operability and accessibility from readily available substrates. The recent discovery of the C═C bond formation through β-C elimination of methylenecyclopropanes (MCP) has provided an exciting opportunity to enhance molecular complexity. In this study, the catalyzed asymmetric cascade hydroboration of MCP is developed. By employing different ligands, various homoallylic boronate intermediate are obtained through the hydroboration ring opening process. Subsequently, the cascade hydroboration with HBpin or B2pin2 resulted in the synthesis of enantioenriched chiral 1,3- and 1,4-bis(boronates) in high yields, accompanied by excellent chemo- and enantioselectivities. The selective transformation of these two distinct C─B bonds also demonstrated their application potential in organic synthesis.
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Affiliation(s)
- Jian Zhou
- Department of Chemistry, Hong Kong Baptist University, Kowloon, Hong Kong, China
| | - Ling Meng
- Department of Chemistry, Hong Kong Baptist University, Kowloon, Hong Kong, China
| | - Ziyi Yang
- Department of Chemistry, Hong Kong Baptist University, Kowloon, Hong Kong, China
| | - Jun Joelle Wang
- Department of Chemistry, Hong Kong Baptist University, Kowloon, Hong Kong, China
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2
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Zhou J, Meng L, Lin S, Cai B, Wang J. Palladium-catalyzed Enantio- and Regioselective Ring-Opening Hydrophosphinylation of Methylenecyclopropanes. Angew Chem Int Ed Engl 2023:e202303727. [PMID: 37186017 DOI: 10.1002/anie.202303727] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/17/2023]
Abstract
Transition metal-catalyzed hydrofunctionalization of methylenecyclopropanes (MCP) has presented a considerable challenge due to the difficult manipulation of regioselectivity and complicated reaction patterns. Herein, we report a straightforward Pd-catalyzed ring-opening hydrophosphinylation reaction of MCP via highly selective C-C bond cleavage. This allows for rapid and efficient access to a wide range of chiral allylic phosphine oxides in good yields and high enantioselectivities. Additionally, density functional theory (DFT) calculations were performed to elucidate the reaction mechanism and the origin of product enantioselectivity.
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Affiliation(s)
- Jian Zhou
- Hong Kong Baptist University, Department of Chemistry, HONG KONG
| | - Ling Meng
- Hong Kong Baptist University, Department of Chemistry, HONG KONG
| | - Shujuan Lin
- Chinese Academy of Sciences Fujian Institute of Research on the Structure of Matter, Department of Chemistry, CHINA
| | - Baohua Cai
- Southern University of Science and Technology, Department of Chemistry, CHINA
| | - Jun Wang
- Hong Kong Baptist University, Department of Chemistry, Ho Sin Hang Campus, 000000, Hong Kong, HONG KONG
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3
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Hu L, Gao H, Hu Y, Lv X, Wu Y, Lu G. Computational insights into strain-increase allylborations for alkylidenecyclopropanes. Chem Commun (Camb) 2022; 58:7034-7037. [DOI: 10.1039/d2cc02264h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The origins of reactivity of strain-increase allylborations were computationally investigated. The low reactivity of vinylcyclopropyl boronates is due to weak electronic interactions between benzaldehyde and allylboronates. By increasing the acidity...
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4
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Hari DP, Madhavachary R, Fasano V, Haire J, Aggarwal VK. Highly Diastereoselective Strain-Increase Allylborations: Rapid Access to Alkylidenecyclopropanes and Alkylidenecyclobutanes. J Am Chem Soc 2021; 143:7462-7470. [PMID: 33950678 DOI: 10.1021/jacs.1c01966] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Allylboration of carbonyl compounds is one of the most widely used methods in the stereoselective synthesis of natural products. However, these powerful transformations are so far limited to allyl- or crotylboron reagents; ring-strained substituents in the α-position have not been investigated. Such substrates would lead to an increase in strain energy upon allylboration and as such cause a significant increase in the activation barrier of the reaction. Indeed, no reaction was observed between an α-cyclopropyl allylboronic ester and an aldehyde. However, by converting the boronic ester into the much more reactive borinic ester, the allylboration proceeded well giving alkylidenecyclopropanes in high yield. This process was highly diastereoselective and gives rapid access to versatile alkylidenecyclopropanes and alkylidenecyclobutanes. The chemistry shows a broad substrate scope in terms of both the range of vinylcycloalkyl boronic esters and aldehydes that can be employed. The intermediate boronate complexes were also found to be potent nucleophiles, reacting with a range of non-carbonyl-based electrophiles and radicals, leading to an even broader range of alkylidenecyclopropanes and alkylidenecyclobutanes. Using 11B NMR experiments, we were able to track the intermediates involved, and DFT calculations supported the experimental findings.
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Affiliation(s)
- Durga Prasad Hari
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | | | - Valerio Fasano
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Jack Haire
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Varinder K Aggarwal
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
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5
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Ramesh B, Jeganmohan M. Cobalt(iii)-catalyzed redox-neutral [4+2]-annulation of N-chlorobenzamides/acrylamides with alkylidenecyclopropanes at room temperature. Chem Commun (Camb) 2021; 57:3692-3695. [PMID: 33725082 DOI: 10.1039/d1cc00654a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
An efficient synthesis of substituted 3,4-dihydroisoquinolinones through [4+2]-annulation of N-chlorobenzamides/acrylamides having a monodentate directing group with alkylidenecyclopropanes in the presence of a less expensive, highly abundant and air stable Co(iii) catalyst via a C-H activation is demonstrated. In this reaction, the N-Cl bond of N-chlorobenzamide serves as an internal oxidant and thus an external metal oxidant is avoided. The 3,4-dihydroisoquinolinone derivatives are converted successfully into the highly useful imidoyl chloride derivatives. The deuterium labeling and kinetic isolabelling studies reveal that the C-H activation is a rate-determining step in this cyclization reaction.
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Affiliation(s)
- Balu Ramesh
- Department of Chemistry, Indian Institute of Technology Madras, Chennai-600036, India.
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6
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Braconi E, Cramer N. A Chiral Naphthyridine Diimine Ligand Enables Nickel-Catalyzed Asymmetric Alkylidenecyclopropanations. Angew Chem Int Ed Engl 2020; 59:16425-16429. [PMID: 32521105 DOI: 10.1002/anie.202006082] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Indexed: 12/17/2022]
Abstract
A novel class of chiral naphthyridine diimine ligands (NDI*) readily accessible from C2 -symmetric 2,6-di-(1-arylethyl)anilines is described. The utility of these ligands, particularly one with fluorinated aryl side arms, is demonstrated by a reductive Ni-catalyzed enantioselective alkylidene transfer reaction from 1,1-dichloroalkenes to olefins. This transformation provides direct access to a broad range of synthetically valuable alkylidenecyclopropanes in high yields and enantioselectivities.
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Affiliation(s)
- Elena Braconi
- Institute of Chemical Sciences and Engineering (ISIC), EPFL SB ISIC LCSA, BCH 4305, 1015, Lausanne, Switzerland
| | - Nicolai Cramer
- Institute of Chemical Sciences and Engineering (ISIC), EPFL SB ISIC LCSA, BCH 4305, 1015, Lausanne, Switzerland
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7
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Braconi E, Cramer N. A Chiral Naphthyridine Diimine Ligand Enables Nickel‐Catalyzed Asymmetric Alkylidenecyclopropanations. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Elena Braconi
- Institute of Chemical Sciences and Engineering (ISIC)EPFL SB ISIC LCSA, BCH 4305 1015 Lausanne Switzerland
| | - Nicolai Cramer
- Institute of Chemical Sciences and Engineering (ISIC)EPFL SB ISIC LCSA, BCH 4305 1015 Lausanne Switzerland
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8
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Hari DP, Abell JC, Fasano V, Aggarwal VK. Ring-Expansion Induced 1,2-Metalate Rearrangements: Highly Diastereoselective Synthesis of Cyclobutyl Boronic Esters. J Am Chem Soc 2020; 142:5515-5520. [PMID: 32146807 DOI: 10.1021/jacs.0c00813] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The broad synthetic utility of organoboron compounds stems from their ready ability to undergo 1,2-migrations. Normally, such shifts are induced by α-leaving groups or by reactions of alkenyl boronates with electrophiles. Herein, we present a new strategy to induce 1,2-metalate rearrangements, via ring expansion of vinylcyclopropyl boronate complexes activated by electrophiles. This leads to a cyclopropane-stabilized carbocation, which triggers ring expansion and concomitant 1,2-metalate rearrangement. This novel process delivers medicinally relevant 1,2-substituted cyclobutyl boronic esters with high levels of diastereoselectivity. A wide range of organolithiums and Grignard reagents, electrophiles, and vinylcyclopropyl boronic esters can be used. The methodology was applied to a short, stereoselective synthesis of (±)-grandisol. Computational studies indicate that the reaction proceeds via a nonclassical carbocation followed by anti-1,2-migration.
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Affiliation(s)
- Durga Prasad Hari
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Joseph C Abell
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Valerio Fasano
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Varinder K Aggarwal
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
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9
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Li Q, Yuan X, Li B, Wang B. The regioselective annulation of alkylidenecyclopropanes by Rh(iii)-catalyzed C–H/C–C activation to access spirocyclic benzosultams. Chem Commun (Camb) 2020; 56:1835-1838. [DOI: 10.1039/c9cc09621c] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of spirocyclic benzosultams fromN-sulfonyl ketimine and alkylidenecyclopropanes under Rh(iii) catalysis has been developed. This transformation enables the formation of two C–C bonds and a double bond with highE-selectivity.
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Affiliation(s)
- Qiuyun Li
- State Key Laboratory of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- P. R. China
| | - Xin Yuan
- Tanggu No. 1 High School
- Tianjin 300450
- People's Republic of China
| | - Bin Li
- State Key Laboratory of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- P. R. China
| | - Baiquan Wang
- State Key Laboratory of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- P. R. China
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10
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Li Q, Yu L, Wei Y, Shi M. Synthesis of Diiodinated All-Carbon 3,3′-Diphenyl-1,1′-spirobiindene Derivatives via Cascade Enyne Cyclization and Electrophilic Aromatic Substitution. J Org Chem 2019; 84:9282-9296. [DOI: 10.1021/acs.joc.9b01418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Quanzhe Li
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Liuzhu Yu
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Yin Wei
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai, 200032, China
| | - Min Shi
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai, 200032, China
- Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, Guangdong 518000, China
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11
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Fang W, Wei Y, Shi M. Palladium(II)‐Catalyzed Intermolecular Cascade Cyclization of Methylenecyclopropanes with Aromatic Alkynes: Construction of Spirocyclic Compounds Containing Indene and 1,2‐Dihydronaphthalene Moieties. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900327] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Wei Fang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular SynthesisUniversity of Chinese Academy of Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 People's Republic of China
| | - Yin Wei
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular SynthesisUniversity of Chinese Academy of Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 People's Republic of China
| | - Min Shi
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular SynthesisUniversity of Chinese Academy of Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 People's Republic of China
- State Key Laboratory and Institute of Elemento-organic ChemistryNankai University Tianjin 300071 People's Republic of China
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12
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Dey A, Thrimurtulu N, Volla CMR. Cobalt-Catalyzed Annulation Reactions of Alkylidenecyclopropanes: Access to Spirocyclopropanes at Room Temperature. Org Lett 2019; 21:3871-3875. [DOI: 10.1021/acs.orglett.9b01392] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arnab Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Neetipalli Thrimurtulu
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Chandra M. R. Volla
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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13
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Fang W, Wei Y, Shi M. Palladium(0)-Catalyzed Intramolecular Cascade Cyclization of Methylenecyclopropanes. Org Lett 2018; 20:7141-7144. [DOI: 10.1021/acs.orglett.8b03084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wei Fang
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Yin Wei
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, University of Chinese Academy of Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Min Shi
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, University of Chinese Academy of Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
- State Key Laboratory and Institute of Elemento-organic Chemistry, Nankai University, Tianjin 300071, P. R. China
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14
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Dian L, Marek I. Asymmetric Preparation of Polysubstituted Cyclopropanes Based on Direct Functionalization of Achiral Three-Membered Carbocycles. Chem Rev 2018; 118:8415-8434. [DOI: 10.1021/acs.chemrev.8b00304] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Longyang Dian
- Schulich Faculty of Chemistry, Technion − Israel Institute of Technology, Haifa 32000, Israel
| | - Ilan Marek
- Schulich Faculty of Chemistry, Technion − Israel Institute of Technology, Haifa 32000, Israel
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15
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Chen PH, Billett BA, Tsukamoto T, Dong G. "Cut and Sew" Transformations via Transition-Metal-Catalyzed Carbon-Carbon Bond Activation. ACS Catal 2017; 7:1340-1360. [PMID: 29062586 PMCID: PMC5650109 DOI: 10.1021/acscatal.6b03210] [Citation(s) in RCA: 312] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The transition metal-catalyzed "cut and sew" transformation has recently emerged as a useful strategy for preparing complex molecular structures. After oxidative addition of a transition metal into a carbon-carbon bond, the resulting two carbon termini can be both functionalized in one step via the following migratory insertion and reductive elimination with unsaturated units, such as alkenes, alkynes, allenes, CO and polar multiple bonds. Three- or four-membered rings are often employed as reaction partners due to their high ring strains. The participation of non-strained structures generally relies on cleavage of a polar carbon-CN bond or assistance of a directing group.
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Affiliation(s)
- Peng-Hao Chen
- Department of Chemistry, University of Texas at Austin, 100 East 24th street, Austin, Texas, 78712 (USA)
| | - Brent A Billett
- Department of Chemistry, University of Chicago, 5735 S. Ellis Ave., Chicago, Illinois, 60637 (USA), Homepage: https://donggroup-sites.uchicago.edu
| | - Tatsuhiro Tsukamoto
- Department of Chemistry, University of Chicago, 5735 S. Ellis Ave., Chicago, Illinois, 60637 (USA), Homepage: https://donggroup-sites.uchicago.edu
| | - Guangbin Dong
- Department of Chemistry, University of Chicago, 5735 S. Ellis Ave., Chicago, Illinois, 60637 (USA), Homepage: https://donggroup-sites.uchicago.edu
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16
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Fumagalli G, Stanton S, Bower JF. Recent Methodologies That Exploit C-C Single-Bond Cleavage of Strained Ring Systems by Transition Metal Complexes. Chem Rev 2017; 117:9404-9432. [PMID: 28075115 DOI: 10.1021/acs.chemrev.6b00599] [Citation(s) in RCA: 639] [Impact Index Per Article: 91.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this review, synthetic and mechanistic aspects of key methodologies that exploit C-C single-bond cleavage of strained ring systems are highlighted. The focus is on transition-metal-catalyzed processes that are triggered by C-C bond activation and β-carbon elimination, with the review concentrating on developments from mid-2009 to mid-2016.
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Affiliation(s)
- Gabriele Fumagalli
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
| | - Steven Stanton
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
| | - John F Bower
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
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17
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Shaw MH, Bower JF. Synthesis and applications of rhodacyclopentanones derived from C-C bond activation. Chem Commun (Camb) 2016; 52:10817-29. [PMID: 27385089 PMCID: PMC5010148 DOI: 10.1039/c6cc04359c] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Rhodacyclopentanones, an "sp(3)-rich" class of metallacycle, underpin an emerging range of catalytic methodologies for the direct generation of complex scaffolds. This review highlights strategies for accessing rhodacyclopentanones (and related species) by C-C bond activation of cyclobutanones or cyclopropanes. The scope and mechanism of methodologies that exploit these activation modes is outlined.
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Affiliation(s)
- Megan H Shaw
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
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18
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Duarte DJR, Miranda MS, Esteves da Silva JCG, Liebman JF. Theoretical characterization of the chemical bonds of some three-membered ring compounds through QTAIM theory. Struct Chem 2015. [DOI: 10.1007/s11224-015-0606-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Zhu PL, Zhang Z, Tang XY, Marek I, Shi M. Gold- and Silver-Catalyzed Intramolecular Cyclizations of Indolylcyclopropenes for the Divergent Synthesis of Azepinoindoles and Spiroindoline Piperidines. ChemCatChem 2015. [DOI: 10.1002/cctc.201402940] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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20
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Timmerman JC, Robertson BD, Widenhoefer RA. Gold-catalyzed intermolecular anti-markovnikov hydroamination of alkylidenecyclopropanes. Angew Chem Int Ed Engl 2014; 54:2251-4. [PMID: 25533892 DOI: 10.1002/anie.201410871] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 11/26/2014] [Indexed: 11/10/2022]
Abstract
The cationic gold phosphine complex [{PCy2 (o-biphenyl)}Au(NCMe)](+) SbF6 (-) (Cy=cyclohexyl) catalyzes the intermolecular, anti-Markovnikov hydroamination reaction of monosubstituted and cis- and trans-disubstituted alkylidenecyclopropanes (ACPs) with imidazolidin-2-ones and other nucleophiles. This reaction forms 1-cyclopropyl alkylamine derivatives in high yield and with high regio- and diastereoselectivity. NMR spectroscopic analysis of gold π-ACP complexes and control experiments point to the sp hybridization of the ACP internal alkene carbon atom as controlling the regiochemistry of the ACP hydroamination reaction.
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Affiliation(s)
- Jacob C Timmerman
- French Family Science Center, Duke University, Durham, NC 27708-0346 (USA)
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21
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Timmerman JC, Robertson BD, Widenhoefer RA. Gold-Catalyzed Intermolecular Anti-Markovnikov Hydroamination of Alkylidenecyclopropanes. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201410871] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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22
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Recent developments in the synthesis and reactivity of methylene- and alkylidenecyclopropane derivatives. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.04.057] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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23
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Mao J, Bao W. Palladium(0)-Catalyzed Methylenecyclopropanation of Norbornenes with Vinyl Bromides. Org Lett 2014; 16:2646-9. [DOI: 10.1021/ol500829t] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Jiangang Mao
- Department
of Chemistry, Zhejiang University, Hangzhou 310027, China
- School
of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Weiliang Bao
- Department
of Chemistry, Zhejiang University, Hangzhou 310027, China
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24
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Miranda MS, Esteves da Silva JCG, Castillo A, Frank AT, Greer A, Brown JA, Davis BC, Liebman JF. Amino, Ammonio and Aminioethenes: A Theoretical Study of their Structure and Energetics. J PHYS ORG CHEM 2013; 26:613-625. [PMID: 24019594 DOI: 10.1002/poc.3140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have performed high level ab initio quantum mechanical calculations for aminoethene and the three isomeric 1,1- (Z)- or (E)-1,2-diaminoethenes as well as their singly and doubly charged cations derived by loss of electrons and/or upon protonation. Gas phase molecular structures were computed at the MP2/6-311+G(3df,2p) level. Standard molar enthalpies of formation in the gas phase, at T = 298.15 K were estimated using the G3 composite method and atomization, isodesmic and homodesmotic reactions. Other energetic parameters were also calculated at the G3 level: proton affinities, basicities and adiabatic ionization enthalpies. Theoretical and experimental data are compared. The reported experimental data refer only to aminoethene wherein the standard molar enthalpy of formation has a considerable uncertainty, although the molecular structure is well-established. There are no such data, neither structural nor thermochemical, for any of the three isomeric diaminoethenes. Isoelectronic comparisons are made. For example, the diprotonated diaminoethenes are isoelectronic to isobutene and (Z)- and (E)-butene, while the doubly ionized diaminoethenes are likewise related to trimethylenemethane and 1,3-butadiene.
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Affiliation(s)
- Margarida S Miranda
- Centro de Geologia da Universidade do Porto, Rua do Campo Alegre, s/n, P-4169-007 Porto, Portugal
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25
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Felix RJ, Gutierrez O, Tantillo DJ, Gagné MR. Gold(I)-catalyzed formation of bicyclo[4.2.0]oct-1-enes. J Org Chem 2013; 78:5685-90. [PMID: 23663099 DOI: 10.1021/jo400139g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Gold(I) catalysts effectively promote the Cope rearrangement of acyclic 1,5-dienes bearing a terminal cyclopropylidene. When this methodology is applied to cyclic substrates an unexpected transformation occurs, resulting in the formation of a tricyclic compound incorporating a bicyclo[4.2.0]oct-1-ene core, a portion of which is found in a number of natural products. Density functional theory calculations (M06 and M06-2X) reveal insight into the mechanism and thermodynamics of this unique transformation.
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Affiliation(s)
- Ryan J Felix
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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26
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Morgan KM, Ellis JA, Lee J, Fulton A, Wilson SL, Dupart PS, Dastoori R. Thermochemical studies of epoxides and related compounds. J Org Chem 2013; 78:4303-11. [PMID: 23551240 DOI: 10.1021/jo4002867] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gas-phase heats of formation for the four butene oxide isomers are reported. They were obtained by measuring the condensed-phase heat of reduction to the corresponding alcohol using reaction calorimetry. Heats of vaporization were determined and allow gas-phase heats of formation to be obtained. The experimental measurements are compared to calculations obtained using a variety of computational methods. Overall, the G3 and CBS-APNO methods agree quite well with the experimental data. The influence of alkyl substituents on epoxide stability is discussed. Comparisons to alkenes, cyclopropanes, aziridines, thiiranes, and phosphiranes are also made. Isodesmic-type reactions were used to determine strain energies of the epoxides and related compounds with various substituents.
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Affiliation(s)
- Kathleen M Morgan
- Department of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans Louisiana 70125, United States.
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27
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Wiberg KB. Accuracy of Calculations of Heats of Reduction/Hydrogenation: Application to Some Small Ring Systems. J Org Chem 2012; 77:10393-8. [DOI: 10.1021/jo302118b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kenneth B. Wiberg
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107,
United States
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28
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A gold-catalysed enantioselective Cope rearrangement of achiral 1,5-dienes. Nat Chem 2012; 4:405-9. [PMID: 22522261 DOI: 10.1038/nchem.1327] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 03/08/2012] [Indexed: 12/25/2022]
Abstract
Since the discovery of the Cope rearrangement in the 1940s, no asymmetric variant of the rearrangement of achiral 1,5-dienes has emerged, despite the successes that have been achieved with its heteroatom variants (Claisen, aza-Cope, and so on). This article reports the first example of an enantioselective Cope reaction that starts from an achiral diene. The new gold(I) catalyst derived from double Cl(-)-abstraction of ((S)-3,5-xylyl-PHANEPHOS(AuCl)(2)), has been developed for the sigmatropic rearrangement of alkenyl-methylenecyclopropanes. The reaction proceeds at low temperature and the synthetically useful vinylcyclopropane products are obtained in high yield and enantioselectivity. Density functional theory calculations predict that: (1) the reaction proceeds via a cyclic carbenium ion intermediate, (2) the relief of strain in the methylenecyclopropane moiety provides the thermodynamic driving force for the rearrangement and (3) metal complexation of the transition-state structure lowers the rearrangement barriers.
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29
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Siebert MR, Tantillo DJ. Fundamental properties of N
-alkenylaziridines-implications for the design of new reactions and organocatalysts. J PHYS ORG CHEM 2011. [DOI: 10.1002/poc.1776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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30
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Zhu ZB, Chen K, Wei Y, Shi M. Preparation of Di-μ-chlorobis[π-1-chloro-1-aryl-2-(2′,2′-diarylvinyl)allyl]palladium(II) Complexes and a Novel Dehydrogenative Rearrangement of Arylvinylcyclopropenes for the Synthesis of 7H-Benzo[c]fluorene Derivatives. Organometallics 2011. [DOI: 10.1021/om1009846] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhi-Bin Zhu
- Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Mei-Long Road, Shanghai 200237, People's Republic of China
| | - Kai Chen
- Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Mei-Long Road, Shanghai 200237, People's Republic of China
| | - Yin Wei
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, People's Republic of China
| | - Min Shi
- Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Mei-Long Road, Shanghai 200237, People's Republic of China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, People's Republic of China
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31
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Li C, Zeng Y, Zhang H, Feng J, Zhang Y, Wang J. Gold(I)-catalyzed cycloisomerization of enynes containing cyclopropenes. Angew Chem Int Ed Engl 2010; 49:6413-7. [PMID: 20672265 DOI: 10.1002/anie.201002673] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Changkun Li
- Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
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32
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Li C, Zeng Y, Zhang H, Feng J, Zhang Y, Wang J. Gold(I)-Catalyzed Cycloisomerization of Enynes Containing Cyclopropenes. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201002673] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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33
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Li C, Zhang H, Feng J, Zhang Y, Wang J. Rh(I)-Catalyzed Carbonylative Carbocyclization of Tethered Ene− and Yne−cyclopropenes. Org Lett 2010; 12:3082-5. [DOI: 10.1021/ol101091r] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Changkun Li
- Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China, and State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hang Zhang
- Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China, and State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jiajie Feng
- Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China, and State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yan Zhang
- Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China, and State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jianbo Wang
- Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China, and State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
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34
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Audran G, Pellissier H. Synthesis of Methylene- and Alkylidenecyclopropane Derivatives. Adv Synth Catal 2010. [DOI: 10.1002/adsc.200900872] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Simaan S, Masarwa A, Zohar E, Stanger A, Bertus P, Marek I. Cyclopropenylcarbinol Derivatives as New Versatile Intermediates in Organic Synthesis: Application to the Formation of Enantiomerically Pure Alkylidenecyclopropane Derivatives. Chemistry 2009; 15:8449-8464. [PMID: 19609999 DOI: 10.1002/chem.200901074] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Samah Simaan
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, and the Lise Meitner-Minerva, Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000 (Israel), Fax: (+972) 4 829 3709
| | - Ahmad Masarwa
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, and the Lise Meitner-Minerva, Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000 (Israel), Fax: (+972) 4 829 3709
| | - Elinor Zohar
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, and the Lise Meitner-Minerva, Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000 (Israel), Fax: (+972) 4 829 3709
| | - Amnon Stanger
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, and the Lise Meitner-Minerva, Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000 (Israel), Fax: (+972) 4 829 3709
| | - Philippe Bertus
- CNRS UMR 6011, Unite de Chimie Organique et Moleculaire (UCO2M), Universite du Maine, Avenue O. Messian, 72085 Le Mans Cedex 9 (France)
| | - Ilan Marek
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, and the Lise Meitner-Minerva, Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000 (Israel), Fax: (+972) 4 829 3709
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36
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Volta L, Stirling CJM. Methylenecyclopropanes in Elimination and Addition Reactions: Quantification of the Effects of Strain. PHOSPHORUS SULFUR 2009. [DOI: 10.1080/10426500902947856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Luca Volta
- a Department of Chemistry , The University of Sheffield , Sheffield, UK
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37
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Creary X, Kochly ED. Systematic Repression of β-Silyl Carbocation Stabilization. J Org Chem 2009; 74:2134-44. [DOI: 10.1021/jo802722z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Xavier Creary
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Elizabeth D. Kochly
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
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38
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Marek I, Simaan S, Masarwa A. Enantiomerically enriched cyclopropene derivatives: versatile building blocks in asymmetric synthesis. Angew Chem Int Ed Engl 2007; 46:7364-76. [PMID: 17663496 DOI: 10.1002/anie.200604774] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Enantiomerically enriched cyclopropene derivatives, the smallest possible unsaturated carbocycles, are of great synthetic interest since they serve as versatile reactive building blocks. Their reactivity results from the relief of the ring strain in the small molecule. They can be transformed into a wide variety of complex chiral structures and a special emphasis will be directed towards the preparation of enantiomerically enriched methylene- and alkylidenecyclopropane derivatives. The ready availability of a wide range of these chiral entities now provides an excellent opportunity to discover new and unique transformations that can further enrich mainstream synthetic methodology.
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Affiliation(s)
- Ilan Marek
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, Israel.
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39
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Bach RD, Dmitrenko O. The effect of carbonyl substitution on the strain energy of small ring compounds and their six-member ring reference compounds. J Am Chem Soc 2007; 128:4598-611. [PMID: 16594697 DOI: 10.1021/ja055086g] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High level ab initio calculations have been applied to the estimation of ring strain energies (SE) of a series of three- and six-member ring compounds. The SE of cyclohexane has been estimated to be 2.2 kcal/mol at the CBS-APNO level of theory. The SE of cyclopropane has been increased to 28.6 kcal/mol after correction for the one-half of the SE of cyclohexane. The SEs of a series of carbonyl-containing three-member ring compounds have been estimated at the CBS-Q level by their combination with cyclopropane to produce a six-member ring reference compound. The SEs of cyclopropanone (5), the simplest alpha-lactone (6) [oxiranone], and alpha-lactam (7) [aziridinone] have been predicted to be 49, 47, and 55 kcal/mol, respectively, after correction for the SE of the corresponding six-member ring reference compound. The SEs of cyclohexanone, delta-valerolactone, and delta-valerolactam have been estimated to be 4.3, 11.3, and 5.1 kcal/mol, respectively. Marked increases in the SE of silacyclopropane and siladioxirane have been established, while significant decreases in the SEs of phosphorus, sulfur, dioxa- and diaza-containing three-member ring compounds were observed. The ring strain energies of the hydrocarbons (but not heterocycles) exhibit a strong correlation with their C-H bond dissociation energies.
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Affiliation(s)
- Robert D Bach
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
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40
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Marek I, Simaan S, Masarwa A. Enantiomerenangereicherte Cyclopropene: vielseitige Bausteine in der asymmetrischen Synthese. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604774] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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41
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Rubin M, Rubina M, Gevorgyan V. Transition metal chemistry of cyclopropenes and cyclopropanes. Chem Rev 2007; 107:3117-79. [PMID: 17622181 DOI: 10.1021/cr050988l] [Citation(s) in RCA: 1052] [Impact Index Per Article: 61.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael Rubin
- Department of Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, Kansas 66045, USA.
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42
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Creary X, Losch A, Sullivan W. Triplet Energy Dissipation in Methylenecyclopropane Rearrangement. J Org Chem 2007; 72:7930-8. [PMID: 17854224 DOI: 10.1021/jo071114x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Certain 1,1-dimethyl-2-aryl-3-methylenecyclopropanes containing carbonyl substituents undergo rearrangement when irradiated with 350 nm light. These rearrangements occur via the (n,pi*) triplet state, which fragments the strained cyclopropane bond. Intersystem crossing followed by ring closure gives the observed products. No photoreduction is seen in i-PrOH. Potential Norrish type II processes are also bypassed. It is suggested that the cyclopropane bond fragmentation dissipates the triplet energy and that the new intermediates are not energetic enough to abstract hydrogen atoms in an intramolecular fashion or from solvent. Nitro substituted systems undergo analogous photoinitiated rearrangements. Benzophenone sensitization of naphthyl, biphenyl, styrene, and phenylacetylene analogues also leads to rearrangement, presumably via the sensitized generation of triplet states. When triplet states cannot be accessed by direct irradiation or by sensitized processes, methylenecyclopropane rearrangements do not occur. An exception is the ferrocenyl analogue, which does not photorearrange, presumably due to the very short lifetime of the triplet intermediate.
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Affiliation(s)
- Xavier Creary
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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43
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Wei H, Hrovat DA, Dolbier WR, Smart BE, Borden WT. The “Bond-Stretched Invertomer” of Hexafluorocyclopropane—a New Type of Reactive Intermediate. Angew Chem Int Ed Engl 2007; 46:2666-8. [PMID: 17335092 DOI: 10.1002/anie.200604574] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Haiyan Wei
- Department of Chemistry, University of North Texas, P.O. Box 305070, Denton, TX 76205-5070, USA
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44
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Wei H, Hrovat D, Dolbier W, Smart B, Borden W. The “Bond-Stretched Invertomer” of Hexafluorocyclopropane-a New Type of Reactive Intermediate. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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45
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Schill H, Kozhushkov SI, Walsh R, de Meijere A. The Thermal Transformations of Bicyclopropylidene and Methylenespiropentane Revisited. European J Org Chem 2007. [DOI: 10.1002/ejoc.200601100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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46
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Shelton GR, Hrovat DA, Wei H, Borden WT. Why Does Perfluorination Render Bicyclo[2.2.0]hex-1(4)-ene Stable toward Dimerization? Calculations Provide the Answers. J Am Chem Soc 2006; 128:12020-7. [PMID: 16953645 DOI: 10.1021/ja063848h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
B3LYP calculations with two different basis sets have been performed to understand why bicyclo[2.2.0]hex-1(4)-ene (1a) undergoes dimerization with DeltaH(++) = 11.5 kcal/mol, but dimerization of perfluorobicyclo[2.2.0]hex-1(4)-ene (1b) has never been observed. The former reaction is computed to be exothermic by 37.2 kcal/mol, whereas the latter is calculated to be endothermic by 7.4 kcal/mol. The 44.6 kcal/mol difference between the enthalpies of these two reactions can be dissected into contributions of 24.5 kcal/mol for the difference between the enthalpies for forming diradical intermediates 2a and 2b and 20.1 kcal/mol for cyclization of 2a and 2b to, respectively, 3a and 3b. The latter enthalpy difference is largely attributable to repulsions between the endo-fluorines in the dimer, although the exo-fluorines also are found to contribute. The former enthalpy difference is attributable to the difference between the dissociation enthalpies of the pi bonds in 1a and 1b, which is shown to amount to 16 +/- 1 kcal/mol. About 25% of the stronger pi bond in fluoroalkene 1b is found to be due to hyperconjugation of the eight C-F bonds in 1b with the filled pi orbital. However, the major contributor to the stronger pi bond in 1b is shown to be the unfavorable interaction that results when a pyramidalized radical center is syn to a C-F bond. Both of these effects, which contribute to the greater strength of the pi bond in 1b, relative to that in 1a, are analyzed and discussed.
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Affiliation(s)
- G Robert Shelton
- Department of Chemistry, University of North Texas, P.O. Box 305070, Denton, Texas 76203-5070, USA
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47
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48
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Bach RD, Dmitrenko O. Strain energy of small ring hydrocarbons. Influence of C-h bond dissociation energies. J Am Chem Soc 2004; 126:4444-52. [PMID: 15053635 DOI: 10.1021/ja036309a] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ab initio calculations at the G2, G3, and CBS-Q levels of theory have been applied to the question of the origin of ring strain in a series of unsaturated hydrocarbons. In addition to the angular ring strain germane to all three-membered ring hydrocarbons, a general trend is in evidence that suggests that the increased ring strain (SE) of unsaturated small ring alkenes may be attributed in part to their relatively weak allylic C-H bonds. The high strain energy of cyclopropene (54.1 kcal/ mol) is attributed largely to angular strain. The anomalously low SE of cyclobutene relative to cyclobutane (DeltaSE = 4 kcal/mol) is a consequence of normal C-H bond dissociation energies for cyclobutane (100.6 kcal/mol) and very strong vinyl C-H bonds (111.9 kcal/mol) and a relatively strong pi-bond energy (63.5 kcal/mol) for cyclobutene. The greater SE of methylenecyclopropane (39.5 kcal/ mol), relative to methylcyclopropane (29.8 kcal/mol), can be attributed to the strong ring C-H bonds of methylcyclopropane (110.5 kcal/mol) and relatively weak allylic C-H bonds (99.3 kcal/mol) of methylenecyclopropane. The increased SE of 1-methylcyclopropene relative to isomeric methylenecyclopropane is ascribed to its weak ring C-H bonds and to angular strain. The relative thermodynamic stability of a series of small ring alkenes is determined by a measure of their hydrogenation enthalpies. Independent confirmation of the SEs of a series of substituted cyclopropenes is provided by their dimerization/combination with cyclopropane to form a six-membered ring reference compound.
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Affiliation(s)
- Robert D Bach
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
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49
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Gal JF, Maria PC, Decouzon M, Mó O, Yáñez M, Abboud JLM. Lithium-cation/pi complexes of aromatic systems. The effect of increasing the number of fused rings. J Am Chem Soc 2003; 125:10394-401. [PMID: 12926964 DOI: 10.1021/ja029843b] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The gas-phase lithium cation basicities (LCBs) of naphthalene, azulene, anthracene, and phenanthrene were measured by means of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The structures of the corresponding complexes and their relative stabilities were investigated at the B3LYP/6-311+G(3df,2p)//B3LYP/6-31G(d) level of theory. In the theoretical survey, pyrene, coronene, [3]phenylene, angular [3]phenylene, and circumcoronene were also included. The strength of the binding to a given aromatic cycle decreases as the number of cycles directly fused to it increases. Hence, the stability of the outer pi-complexes, in which Li(+) is attached to the peripheral rings, is systematically greater than that of the complexes in which the metal is attached to the inner rings. The energy gap between these local minima decreases as the number of fused rings in the system increases. This result seems to indicate that, as the size of the system increases, the rings tend to lose their peculiarities, in such a way that in the limit of a graphite sheet all rings would exhibit identical characteristics and reactivity. The good agreement between calculated LCBs and experimental values lends support to the enhanced stability of the outer complexes. The activation barriers connecting these local minima decrease as the number of fused cycles increases, but seems to tend toward a limit. [3]Phenylene and angular [3]phenylene exhibit enhanced LCBs reflecting nonnegligible Mills-Nixon effects that increase the electron-donor properties of these annelated benzenes.
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Affiliation(s)
- Jean-François Gal
- Chimie des Matériaux Organiques et Métalliques, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2, France
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50
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Park J, Jongsma CG, Zhang R, North SW. Cyclization reactions in isoprene derived β-hydroxy radicals: implications for the atmospheric oxidation mechanism. Phys Chem Chem Phys 2003. [DOI: 10.1039/b306580d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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