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Lepage RJ, Moore PW, Hewitt RJ, Teesdale-Spittle PH, Krenske EH, Harvey JE. Mechanistic Studies on the Base-Promoted Ring Opening of Glycal-Derived gem-Dibromocyclopropanes. J Org Chem 2021; 87:301-315. [PMID: 34932347 DOI: 10.1021/acs.joc.1c02366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the presence of a nucleophilic base, ring-fused gem-dibromocyclopropanes derived from d-glycals undergo ring opening to give 2-deoxy-2-(E-bromomethylene)glycosides. Such cleavage of an exocyclic cyclopropane bond contrasts with the more usual silver-promoted ring-expansion reactions in which endocyclic bond cleavage occurs. Experimental and theoretical studies are reported which provide insights into the reaction mechanism and the origin of its kinetic selectivity for E-configured bromoalkene products. Density functional theory computations (M06-2X) predict that the reaction commences with alkoxide-induced HBr elimination from the dibromocyclopropane to form a bromocyclopropene. Ring opening then gives a configurationally stable zwitterionic (oxocarbenium cation/vinyl carbanion) intermediate, which undergoes nucleophilic addition and protonation to give the bromoalkene. There are two competing sources of the proton in the final step: One is the alcohol (co)solvent, and the other is the molecule of alcohol produced during the initial deprotonation step. The roles of the formed alcohol molecule and the bulk (co)solvent are demonstrated by isotope-labeling studies performed with deuterated solvents. The acid-promoted isomerization of the E-bromoalkene product into the corresponding Z-bromoalkene is also described. The mechanistic knowledge gained in this investigation sheds light on the unusual chemistry of this system and facilitates its future application in new settings.
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Affiliation(s)
- Romain J Lepage
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Peter W Moore
- School of Chemical and Physical Sciences, Centre for Biodiscovery, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
| | - Russell J Hewitt
- School of Chemical and Physical Sciences, Centre for Biodiscovery, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
| | - Paul H Teesdale-Spittle
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
| | - Elizabeth H Krenske
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Joanne E Harvey
- School of Chemical and Physical Sciences, Centre for Biodiscovery, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
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Thorat SS, Kontham R. Strategies for the synthesis of furo-pyranones and their application in the total synthesis of related natural products. Org Chem Front 2021. [DOI: 10.1039/d0qo01421d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The furo-pyranone framework is widely present in the molecular structure of various biologically potent natural products and un-natural small molecules, and it represents a valuable target in synthetic organic chemistry and medicinal chemistry.
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Affiliation(s)
- Sagar S. Thorat
- Organic Chemistry Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Ravindar Kontham
- Organic Chemistry Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
- Academy of Scientific and Innovative Research (AcSIR)
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3
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McCone JAJ, Somarathne KK, Orme CL, Hewitt RJ, Grant ER, Hall KR, Ackerley DF, La Flamme AC, Harvey JE. Total Synthesis and Bioactivity Studies of Fungal Metabolite (-)-TAN-2483B. Org Lett 2020; 22:9427-9432. [PMID: 33232161 DOI: 10.1021/acs.orglett.0c03303] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The first total synthesis of (-)-TAN-2483B, a fungal metabolite possessing a densely functionalized furo[3,4-b]pyran-5-one framework, is achieved in 14 steps from d-mannose. Generation of the 2,6-trans-pyran is by cyclopropane ring expansion followed by α-selective alkynylation. Julia-Kocienski olefination introduces the E-propenyl side chain. Alkyne functionalization and carbonylation stereoselectively establish the bicyclic core of (-)-TAN-2483B. Inhibition of kinases Btk and Bmx, bacterial priority pathogens, and cytokine production in splenocytes indicates promising therapeutic potential.
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Somarathne KK, McCone JAJ, Brackovic A, Rivera JLP, Fulton JR, Russell E, Field JJ, Orme CL, Stirrat HL, Riesterer J, Teesdale‐Spittle PH, Miller JH, Harvey JE. Synthesis of Bioactive Side‐Chain Analogues of TAN‐2483B. Chem Asian J 2019; 14:1230-1237. [DOI: 10.1002/asia.201801767] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/27/2018] [Indexed: 01/13/2023]
Affiliation(s)
- Kalpani K. Somarathne
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - Jordan A. J. McCone
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery Auckland New Zealand
| | - Amira Brackovic
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - José Luis Pinedo Rivera
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - J. Robin Fulton
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - Euan Russell
- School of Biological Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - Jessica J. Field
- School of Biological Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - Christopher L. Orme
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - Hedley L. Stirrat
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - Jasmin Riesterer
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - Paul H. Teesdale‐Spittle
- Maurice Wilkins Centre for Molecular Biodiscovery Auckland New Zealand
- School of Biological Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - John H. Miller
- School of Biological Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
| | - Joanne E. Harvey
- School of Chemical and Physical Sciences, Centre for BiodiscoveryVictoria University of Wellington Wellington New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery Auckland New Zealand
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Abstract
AbstractAddition of a carbene to a glycal is the prominent method for the synthesis of 1,2-cyclopropyl carbohydrates. This incorporation of a cyclopropane into a carbohydrate scaffold enables divergent reactivity, with the two main classes being ring expansion and cleavage to 2-C-branched carbohydrates. A wide variety of products are obtained depending on the functionality attached to the cyclopropane (none or ester or halogens) and the promoter (Lewis acid, Brønsted acid, halophile or base) used in the reaction. This article reviews progress in the synthesis and reactions of 1,2-cyclopropyl carbohydrates since 2000 and discloses efforts by our group in the area.
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Bartlett MJ, Northcote PT, Lein M, Harvey JE. 13C NMR Analysis of 3,6-Dihydro-2H-pyrans: Assignment of Remote Stereochemistry Using Axial Shielding Effects. J Org Chem 2014; 79:5521-32. [DOI: 10.1021/jo500678k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Mark J. Bartlett
- School of Chemical and Physical
Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
| | - Peter T. Northcote
- School of Chemical and Physical
Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
| | - Matthias Lein
- School of Chemical and Physical
Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
| | - Joanne E. Harvey
- School of Chemical and Physical
Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
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Dey S, Jayaraman N. Exclusive ring opening of gem-dihalo-1,2-cyclopropanated oxyglycal to oxepines in AgOAc. Carbohydr Res 2014; 389:66-71. [PMID: 24612864 DOI: 10.1016/j.carres.2014.01.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 01/27/2014] [Accepted: 01/30/2014] [Indexed: 11/29/2022]
Abstract
Treatment of gem-dihalo-1,2-cyclopropanated d-oxyglycal with primary, secondary, and unsaturated alcohols, in the presence of AgOAc, leads to the formation of chloro-oxepines exclusively. Reaction of the resulting 2-chloro-oxepines with excess alcohol in the presence of AgOAc, do not promote further reactions. This result is in contrast to the reactions of d-glucal derived halo-oxepine with alcohols known previously that lead to the formation of furanoses as the major product under similar reaction conditions. Observation of this study consolidates the reactivity differences of gem-dihalo-1,2-cyclopropanated oxyglycals, as compared to gem-dihalo-1,2-cyclopropanated glycals.
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Affiliation(s)
- Supriya Dey
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - N Jayaraman
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
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8
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Affiliation(s)
- Jiayun He
- Department of Chemistry and
State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Jesse Ling
- Department of Chemistry and
State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Pauline Chiu
- Department of Chemistry and
State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong
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Gopi E, Namboothiri INN. Synthesis of Fused Bromofurans via Mg-Mediated Dibromocyclopropanation of Cycloalkanone-Derived Chalcones and Cloke–Wilson Rearrangement. J Org Chem 2013; 78:910-9. [DOI: 10.1021/jo3022988] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elumalai Gopi
- Department of Chemistry, Indian Institute of Technology, Bombay, Mumbai 400 076, India
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