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Levy A, Cohen S, Pogodin S, Agranat I. Selenium- and tellurium-bridged heteromerous overcrowded bistricyclic aromatic enes with central six-member and seven-member rings. Struct Chem 2015. [DOI: 10.1007/s11224-015-0675-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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2
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Kostenko A, Tumanskii B, Karni M, Inoue S, Ichinohe M, Sekiguchi A, Apeloig Y. Observation of a Thermally Accessible Triplet State Resulting from Rotation around a Main-Group π Bond. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201506291] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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3
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Kostenko A, Tumanskii B, Karni M, Inoue S, Ichinohe M, Sekiguchi A, Apeloig Y. Observation of a Thermally Accessible Triplet State Resulting from Rotation around a Main-Group π Bond. Angew Chem Int Ed Engl 2015; 54:12144-8. [DOI: 10.1002/anie.201506291] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 07/27/2015] [Indexed: 11/11/2022]
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Krenske EH, Williams CM. Do Anti-Bredt Natural Products Exist? Olefin Strain Energy as a Predictor of Isolability. Angew Chem Int Ed Engl 2015; 54:10608-12. [PMID: 26235843 DOI: 10.1002/anie.201503822] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Indexed: 01/29/2023]
Abstract
Bredt's rule holds a special place in the realm of physical organic chemistry, but its application to natural products chemistry—the field in which the rule was originally formulated—is not well defined. Herein, the use of olefin strain (OS) energy as a readily calculated predictor of the stability of natural products containing a bridgehead alkene is introduced. Schleyer first used OS energies to classify parent bridgehead alkenes into "isolable", "observable", and "unstable" classes. OS calculations on natural products, using contemporary forcefield methods, unequivocally predict all structurally verified bridgehead alkene natural products to be "isolable". Thus, when one assigns the structure of a putative bridgehead alkene natural product, an OS in the "observable" or "unstable" ranges is a red flag for error.
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Affiliation(s)
- Elizabeth H Krenske
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland (Australia) http://www.scmb.uq.edu.au/homepages/williams/index.html.
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland (Australia) http://www.scmb.uq.edu.au/homepages/williams/index.html.
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Krenske EH, Williams CM. Do Anti-Bredt Natural Products Exist? Olefin Strain Energy as a Predictor of Isolability. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201503822] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Mak JYW, Pouwer RH, Williams CM. Naturstoffe mit Anti-Bredt- und Brückenkopf-Doppelbindung. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400932] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Mak JYW, Pouwer RH, Williams CM. Natural products with anti-Bredt and bridgehead double bonds. Angew Chem Int Ed Engl 2014; 53:13664-88. [PMID: 25399486 DOI: 10.1002/anie.201400932] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/25/2014] [Indexed: 11/11/2022]
Abstract
Well over a hundred years ago, Professor Julius Bredt embarked on a career pursuing and critiquing bridged bicyclic systems that contained ring strain induced by the presence of a bridgehead olefin. These endeavors founded what we now know as Bredt's rule (Bredtsche Regel). Physical, theoretical, and synthetic organic chemists have intensely studied this premise, pushing the boundaries of such systems to arrive at a better understood physical phenomenon. Mother nature has also seen fit to construct molecules containing bridgehead double bonds that encompass Bredt's rule. For the first time, this topic is reviewed in a natural product context.
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Affiliation(s)
- Jeffrey Y W Mak
- Institute for Molecular Bioscience, The University of Queensland, Brisbane (Australia)
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Kanawati B, Genest A, Schmitt-Kopplin P, Lenoir D. Bis-dibenzo[a.i]fluorenylidene, does it exist as stable 1,2-diradical? J Mol Model 2012; 18:5089-95. [DOI: 10.1007/s00894-012-1502-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 06/08/2012] [Indexed: 11/24/2022]
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10
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Camps P, Colet G, Delgado S, Muñoz MR, Pericàs MA, Solà L, Vázquez S. Generation and reactions of new ether and acetal functionalized tricyclo[3.3.0.03,7]oct-1(5)-ene derivatives. DSC and NMR studies on the [2+2] retrocycloaddition of several cyclobutane dimers. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.03.094] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Tsuji T, Ohkita M, Kawai H. Preparation and Kinetic Stabilization of Highly Strained Paracyclophanes. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2002. [DOI: 10.1246/bcsj.75.415] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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Vázquez S. GIAO-DFT study of13C NMR chemical shifts of highly pyramidalized alkenes. ACTA ACUST UNITED AC 2002. [DOI: 10.1039/b207060j] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Camps P, Pujol X, Vázquez S, Pericàs MA, Puigjaner C, Solà L. Cross-coupling of a functionalized highly pyramidalized alkene: DSC and NMR study of the [2+2] retrocycloaddition of cyclobutane cross products, hyperstability and pyramidalization of the formed dienes. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00802-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Voitenko Z, Pocholenko O, Chkarov O, Shishkin O, Shishkina S, Dall’Ava A, Vedrenne M, Sanchez M, Wolf JG. Structure of the Cycloaddition Products of Pyrido[2,1-a]isoindole with Maleimide Derivatives: X-ray Diffraction Analysis and1H NMR Variable-Temperature Spectra. European J Org Chem 2001. [DOI: 10.1002/1099-0690(200104)2001:7<1401::aid-ejoc1401>3.0.co;2-m] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Irngartinger H, Altreuther A, Sommerfeld T, Stojanik T. Pyramidalization in Derivatives of Bicyclo[5.1.0]oct-1(7)-enes and 2,2,5,5-Tetramethylbicyclo[4.1.0]hept-1(6)-enes. European J Org Chem 2000. [DOI: 10.1002/1099-0690(200012)2000:24<4059::aid-ejoc4059>3.0.co;2-v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Interplay of Twisting and Folding in Overcrowded Heteromerous Bistricyclic Aromatic Enes. Org Lett 2000; 2:1811-1814. [PMID: 10891164 DOI: 10.1021/ol005827c] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Fluorenylidenexanthenes 5-7 were synthesized by 2-fold extrusion diazo-thione couplings. 7 exhibited yellow crystals and purple (560 nm) solutions. (1)H NMR of 5 and 7 indicated subtle equilibria twisted (t) right harpoon over left harpoon anti-folded (a) major/minor conformations. (13)C DNMR of 6 gave DeltaG(c)(double dagger)(enantiomerization/inversion) = 26.5 kJ/mol and DeltaG(c)(double dagger)(E,Z-topomerization) = 82.0 kJ/mol. PM3 calculations of 5 revealed minima a, t, ts (twisted/syn-folded), DeltaDeltaH(f) degrees = 0.0, 14.1, 15.6 kJ/mol, and transition states [t-ts], [a-ts], [t( perpendicular)], [a-a], DeltaDeltaH(f) degrees = 16.3, 17.4, 82.2, 99.3 kJ/mol.
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Extremely strained paracyclophanes. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s1527-4640(99)80005-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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Griesbeck AG, Deufel T, Hohlneicher G, Rebentisch R, Steinwascher J. Synthesis, Structure, and Properties of Twofold Bridged Sesquinorbornenes. European J Org Chem 1998. [DOI: 10.1002/(sici)1099-0690(199809)1998:9<1759::aid-ejoc1759>3.0.co;2-i] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Griesbeck AG, Deufel T, Hohlneicher G, Rebentisch R, Steinwascher J. Synthesis, Structure, and Properties of Twofold Bridged Sesquinorbornenes. European J Org Chem 1998. [DOI: 10.1002/(sici)1099-0690(199809)1998:9%3c1759::aid-ejoc1759%3e3.0.co%3b2-i] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Camps P, Font-Bardia M, Méndez N, Pérez F, Pujol X, Solans X, Vázquez S, Vilalta M. Highly pyramidalized tricyclo[3.3.0.03,7]oct-1(5)-ene and related compounds: High-level ab initio study, synthesis and trapping of tetracyclo[5.2.1.02,6.03,8] dec-7-ene, and cross-coupling reactions. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(98)00185-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Overcrowded polycyclic aromatic enes. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s1046-5766(98)80018-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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25
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Trimethylchlorosilane-modified Clemmensen reduction of metallocenyl ketones: trapping and X-ray structures f aliphatic, olefinic, silylated pinacolic, and rearranged pinacolonic products. J Organomet Chem 1996. [DOI: 10.1016/0022-328x(96)06344-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Murty BARC, Pinkos R, Spurr PR, Fessner WD, Lutz G, Fritz H, Hunkler D, Prinzbach H. The Pagodane Route to Dodecahedranes Unsaturated (Hyperstable) and Saturated Bissecododecahedranes. ACTA ACUST UNITED AC 1992. [DOI: 10.1002/cber.19921250728] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fessner WD, Murty BARC, Spurr PR, Pinkos R, Melder JP, Fritz H, Prinzbach H. The Pagodane Route to Dodecahedranes Directed Conversions – The Pagodane → Bissecododecahedradiene Stage. ACTA ACUST UNITED AC 1992. [DOI: 10.1002/cber.19921250727] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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The pagodane route to dodecahedranes-unsaturated dodecahedranes, protection and deprotection. Tetrahedron Lett 1992. [DOI: 10.1016/s0040-4039(00)92326-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Acenaphth[1,2-a]acenaphthylene: a semi-benzenoid hydrocarbon with dienophilic central double bond. Tetrahedron Lett 1991. [DOI: 10.1016/0040-4039(91)80486-p] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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