1
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Antonova YA, Nelyubina YV, Ioffe SL, Tabolin AA. [3+3]-Annulation of Cyclic Nitronates with Vinyl Diazoacetates: Diastereoselective Synthesis of Partially Saturated [1,2]Oxazino[2,3- b][1,2]oxazines and Their Base-Promoted Ring Contraction to Pyrrolo[1,2- b][1,2]oxazine Derivatives. Molecules 2023; 28:molecules28073025. [PMID: 37049788 PMCID: PMC10096057 DOI: 10.3390/molecules28073025] [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: 02/27/2023] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 04/14/2023] Open
Abstract
A rhodium(II)-catalyzed reaction of cyclic nitronates (5,6-dihydro-4H-1,2-oxazine N-oxides) with vinyl diazoacetates proceeds as a [3+3]-annulation producing bicyclic unsaturated nitroso acetals (4a,5,6,7-tetrahydro-2H-[1,2]oxazino[2,3-b][1,2]oxazines). Optimization of reaction conditions revealed the use of Rh(II) octanoate as the preferred catalyst in THF at room temperature, which allows the preparation of target products in good yields and excellent diastereoselectivity. Under basic conditions, namely, the combined action of DBU and alcohol, these nitroso acetals undergo ring contraction of an unsaturated oxazine ring into the corresponding pyrrole. Both transformations can be performed in a one-pot fashion, thus constituting a quick approach to oxazine-annulated pyrroles from available starting materials, such as nitroalkenes, olefins, and diazo compounds.
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Affiliation(s)
- Yulia A Antonova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prosp. 47, Moscow 119991, Russia
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Str. 28, Moscow 119991, Russia
| | - Sema L Ioffe
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prosp. 47, Moscow 119991, Russia
| | - Andrey A Tabolin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prosp. 47, Moscow 119991, Russia
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2
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Nambu H, Tamura T, Yakura T. Protecting-Group-Free Formal Synthesis of Aspidospermidine: Ring-Opening Cyclization of Spirocyclopropane with Amine Followed by Regioselective Alkylations. J Org Chem 2019; 84:15990-15996. [DOI: 10.1021/acs.joc.9b02469] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Hisanori Nambu
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama 930-0194, Japan
| | - Takafumi Tamura
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama 930-0194, Japan
| | - Takayuki Yakura
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama 930-0194, Japan
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3
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Verma P, Chandra A, Pandey G. Diversity-Oriented Approach Toward the Syntheses of Amaryllidaceae Alkaloids via a Common Chiral Synthon. J Org Chem 2018; 83:9968-9977. [PMID: 30005155 DOI: 10.1021/acs.joc.8b01368] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Functionalized hydroindole (1), a common chiral synthon, for versatile transformations to synthesize a broad range of Amaryllidaceae alkaloids (AAs) including (-)-crinine, (-)-crinane, (-)-amabiline, (+)-mesembrine, (-)-maritidine, (-)-oxomaritidine, and (+)-mesembrane is reported. Scaffold 1 is found as a prime structural motif in a wide variety of the AAs and is a novel synthon toward designing a divergent route for the synthesis of these natural products. This is established in a few steps, starting from a chiral aza-bicyclo-heptene sulfone scaffold (2) via conjugate addition and concomitant stereoselective ring opening with allylmagnesium bromide, a key step that generates a crucial quaternary stereocenter, fixing the stereochemistry of the rest of the molecule at an early stage. One carbon truncation followed by intramolecular reductive amination led to the desired core 1 in a multigram scale.
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Affiliation(s)
- Prachi Verma
- Molecular Synthesis and Drug Discovery Lab , Centre of Biomedical Research, SGPGI Campus , Raibarely Road , Lucknow , Uttar Pradesh 226014 , India
| | - Atish Chandra
- Molecular Synthesis and Drug Discovery Lab , Centre of Biomedical Research, SGPGI Campus , Raibarely Road , Lucknow , Uttar Pradesh 226014 , India
| | - Ganesh Pandey
- Molecular Synthesis and Drug Discovery Lab , Centre of Biomedical Research, SGPGI Campus , Raibarely Road , Lucknow , Uttar Pradesh 226014 , India
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4
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Czekelius C. Total Synthesis of Mesembrine - The Construction of Quaternary Stereocenters by Gold-Catalyzed Diyne Desymmetrization. Isr J Chem 2018. [DOI: 10.1002/ijch.201700060] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Constantin Czekelius
- Institute for Organic Chemistry and Macromolecular Chemistry; Heinrich-Heine-Universität Düsseldorf; Universitätsstrasse 1 D-40225 Düsseldorf
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5
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Motornov VA, Tabolin AA, Novikov RA, Nelyubina YV, Nenajdenko VG, Ioffe SL. Fluoronitroalkenes in tandem [4 + 1]/[3 + 2]-cycloaddition: one-pot three-component assembly of fluorinated bicyclic nitroso acetals. Org Chem Front 2018. [DOI: 10.1039/c8qo00623g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Novel fluorinated bicyclic nitroso acetals were obtained in a highly regio- and diastereo-selective manner via tandem [4 + 1]/[3 + 2]-cycloaddition of fluoronitroalkenes.
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Affiliation(s)
- Vladimir A. Motornov
- N. D. Zelinsky Institute of Organic Chemistry
- Russian Academy of Sciences
- Moscow
- Russia
- Higher Chemical College
| | - Andrey A. Tabolin
- N. D. Zelinsky Institute of Organic Chemistry
- Russian Academy of Sciences
- Moscow
- Russia
| | - Roman A. Novikov
- N. D. Zelinsky Institute of Organic Chemistry
- Russian Academy of Sciences
- Moscow
- Russia
- V. A. Engelhardt Institute of Molecular Biology
| | - Yulia V. Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Moscow
- Russia
| | | | - Sema L. Ioffe
- N. D. Zelinsky Institute of Organic Chemistry
- Russian Academy of Sciences
- Moscow
- Russia
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6
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Krstenansky JL. Mesembrine alkaloids: Review of their occurrence, chemistry, and pharmacology. JOURNAL OF ETHNOPHARMACOLOGY 2017; 195:10-19. [PMID: 27939420 DOI: 10.1016/j.jep.2016.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 11/06/2016] [Accepted: 12/05/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Mesembrine alkaloids are considered to be the primary active constituents of the South African medicinal plant Sceletium tortuosum (L.) N.E.Br. (Aizoaceae), and it is used as the dried or fermented aerial material from the plant, which is known as kanna (aka, channa, kougoed). Traditional regional use ranged from relieving thirst, mild analgesia, and alteration of mood. Current interest has focused primarily on the antidepressant action of preparations based on the plant and commercialization is expanding the recognition and availability of these preparations. MATERIALS AND METHODS Searches for the keywords "Sceletium or mesembrine" were performed in "PubMed-NCBI", "Chemical Abstracts SciFinder" and "Thomson Reuters Web of Science" databases in addition to the inclusion of references cited within prior reviews and scientific reports. Additionally the "SciFinder" database was searched using 3a-phenyl-cis-octahydroindole in the SciFinder Substructure Module (SSM). Plant taxonomy was validated by the database "The Plant List". RESULTS This review focuses on the chemistry, analysis, and pharmacology of the mesembrine alkaloids. Despite a long history of medicinal used and research investigation, there has been a renewed interest in the pharmacological properties of the mesembrine alkaloids and much of the pharmacology has only recently been published. The two major active alkaloids mesembrine and mesembrenone are still in the process of being more fully characterized pharmacologically. They are serotonin reuptake inhibitors, which provides a rationale for the plant's traditional use as an antidepressant, but other actions are beginning to appear in the literature. Additionally, mesembrenone has reasonably potent PDE4 inhibitory activity. This review intends to provide an overview of the available literature, summarize the current findings, and put them in perspective with earlier studies and reviews.
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Spittler M, Lutsenko K, Czekelius C. Total Synthesis of (+)-Mesembrine Applying Asymmetric Gold Catalysis. J Org Chem 2016; 81:6100-5. [DOI: 10.1021/acs.joc.6b00985] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael Spittler
- Institute for Organic Chemistry
and Macromolecular Chemistry, Universität Düsseldorf, Universitätsstr.
1, D-40225 Düsseldorf, Germany
| | - Kiril Lutsenko
- Institute for Organic Chemistry
and Macromolecular Chemistry, Universität Düsseldorf, Universitätsstr.
1, D-40225 Düsseldorf, Germany
| | - Constantin Czekelius
- Institute for Organic Chemistry
and Macromolecular Chemistry, Universität Düsseldorf, Universitätsstr.
1, D-40225 Düsseldorf, Germany
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8
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Gan P, Smith MW, Braffman NR, Snyder SA. Pyrone Diels-Alder Routes to Indolines and Hydroindolines: Syntheses of Gracilamine, Mesembrine, and Δ7-Mesembrenone. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510520] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Pei Gan
- Dept. of Chemistry; The Scripps Research Institute; 130 Scripps Way Jupiter FL 33458 USA
| | - Myles W. Smith
- Dept. of Chemistry; Columbia University; 3000 Broadway New York NY 10027 USA
- Dept. of Chemistry; The Scripps Research Institute; 130 Scripps Way Jupiter FL 33458 USA
| | | | - Scott A. Snyder
- Dept. of Chemistry; Columbia University; 3000 Broadway New York NY 10027 USA
- Dept. of Chemistry; The Scripps Research Institute; 130 Scripps Way Jupiter FL 33458 USA
- Dept. of Chemistry; The University of Chicago; 5735 South Ellis Avenue Chicago IL 60637 USA
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9
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Gan P, Smith MW, Braffman NR, Snyder SA. Pyrone Diels-Alder Routes to Indolines and Hydroindolines: Syntheses of Gracilamine, Mesembrine, and Δ7-Mesembrenone. Angew Chem Int Ed Engl 2016; 55:3625-30. [DOI: 10.1002/anie.201510520] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Indexed: 01/04/2023]
Affiliation(s)
- Pei Gan
- Dept. of Chemistry; The Scripps Research Institute; 130 Scripps Way Jupiter FL 33458 USA
| | - Myles W. Smith
- Dept. of Chemistry; Columbia University; 3000 Broadway New York NY 10027 USA
- Dept. of Chemistry; The Scripps Research Institute; 130 Scripps Way Jupiter FL 33458 USA
| | | | - Scott A. Snyder
- Dept. of Chemistry; Columbia University; 3000 Broadway New York NY 10027 USA
- Dept. of Chemistry; The Scripps Research Institute; 130 Scripps Way Jupiter FL 33458 USA
- Dept. of Chemistry; The University of Chicago; 5735 South Ellis Avenue Chicago IL 60637 USA
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10
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Bhosale VA, Ukale DU, Waghmode SB. Total synthesis of Sceletium alkaloids (±)-joubertinamine, (±)-epijoubertinamine, (±)-tortuosamine and formal synthesis of (±)-mesembrine, (±)-N-formyltortuosamine. NEW J CHEM 2016. [DOI: 10.1039/c6nj00630b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
An efficient collective formal/total synthesis of Sceletium alkaloids achieved by employing the Wittig olefination–Claisen rearrangement protocol.
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Affiliation(s)
- Viraj A. Bhosale
- Garware Research Center
- Department of Chemistry
- Savitribai Phule Pune University (formerly University of Pune)
- Pune 411007
- India
| | - Dattatraya U. Ukale
- Garware Research Center
- Department of Chemistry
- Savitribai Phule Pune University (formerly University of Pune)
- Pune 411007
- India
| | - Suresh B. Waghmode
- Garware Research Center
- Department of Chemistry
- Savitribai Phule Pune University (formerly University of Pune)
- Pune 411007
- India
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11
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Das MK, De S, Shubhashish, Bisai A. Concise total syntheses of (±)-mesembrane and (±)-crinane. Org Biomol Chem 2015; 13:3585-8. [PMID: 25698179 DOI: 10.1039/c5ob00183h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A straightforward and unified strategy to access Amaryllidaceae alkaloids comprising a cis-3a-aryloctahydroindole scaffold has been developed. The strategy features Eschenmoser-Claisen rearrangement of allylalcohol as a key step for the installation of all-carbon quaternary stereocenters present in these alkaloids. The consequent iodolactonization-reduction-oxidation sequence beautifully assembles the advanced intermediate keto-aldehyde 10a, b in synthetically viable yields. The methodology has been successfully applied in the efficient syntheses of (±)-mesembrane (1a) and (±)-crinane (2a).
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Affiliation(s)
- Mrinal Kanti Das
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, MP-462066, India.
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12
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Ozaki T, Kobayashi Y. Synthesis of (−)-mesembrine using the quaternary carbon-constructing allylic substitution. Org Chem Front 2015. [DOI: 10.1039/c4qo00353e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Han WB, Li SG, Lu XW, Wu Y. Facile Conversion of Cyclopropanols into Linear Conjugate Enones. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402175] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Gérard H, Chataigner I. Selectivities of Multicomponent [4 + 2]/[3 + 2] Cycloadditions of 3-Nitroindole with Substituted Alkenes: A DFT Analysis. J Org Chem 2013; 78:9233-42. [DOI: 10.1021/jo401482b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Hélène Gérard
- Laboratoire de Chimie Théorique
UMR 7616, UPMC Univ Paris 06, F-75005 Paris,
France
| | - Isabelle Chataigner
- Laboratoire COBRA, CNRS UMR 6014 & FR 3038, Université de Rouen, 76821 Mont St Aignan, France
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15
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Wei MX, Wang CT, Du JY, Qu H, Yin PR, Bao X, Ma XY, Zhao XH, Zhang GB, Fan CA. Enantioselective synthesis of Amaryllidaceae alkaloids (+)-vittatine, (+)-epi-vittatine, and (+)-buphanisine. Chem Asian J 2013; 8:1966-71. [PMID: 23788411 DOI: 10.1002/asia.201300595] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Indexed: 11/10/2022]
Abstract
Cat. on a hot tin roof: Enantioselective catalytic Michael addition of α-cyanoketones to acrylates under bifunctional organocatalysis was used to construct the unique arylic all-carbon quaternary stereocenter, which is synthetically crucial in the chemical synthesis of optically pure cis-aryl hydroindole alkaloids. The protocol offers an asymmetric route to (+)-vittatine, (+)-epi-vittatine, and (+)-buphanisine.
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Affiliation(s)
- Meng-Xue Wei
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
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16
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Kalia D, Merey G, Guo M, Sintim HO. N–O Tethered Carbenoid Cyclopropanation Facilitates the Synthesis of a Functionalized Cyclopropyl-Fused Pyrrolidine. J Org Chem 2013; 78:6131-42. [DOI: 10.1021/jo400788a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Dimpy Kalia
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
| | - Gökce Merey
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
- Chemical Engineering Department, Hitit University, Corum, Turkey
| | - Min Guo
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
| | - Herman O. Sintim
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
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17
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Haym I, Brimble MA. The Kulinkovich hydroxycyclopropanation reaction in natural product synthesis. Org Biomol Chem 2013; 10:7649-65. [PMID: 22886040 DOI: 10.1039/c2ob26082d] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Kulinkovich cyclopropanation reaction provides a flexible and convenient method for the synthesis of cyclopropanols. Together with the diverse chemistry of the cyclopropanol unit, it offers access to a wide range of functionalised unsaturated and saturated compounds. The successful use in the synthesis of natural compounds is outlined in this perspective.
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Affiliation(s)
- Isabell Haym
- University of Auckland, School of Chemical Sciences, 23 Symonds Street, Auckland 1043, New Zealand
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18
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DFT study on the intramolecular nitrone–alkene cycloaddition reaction of the N-3-alkenylnitrone. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2012.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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19
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Six-membered cyclic nitronates in the stereoselective synthesis of natural and bioactive compounds. Chem Heterocycl Compd (N Y) 2012. [DOI: 10.1007/s10593-012-0968-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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20
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Kamimura A, Takeuchi R, Ikeda K, Moriyama T, Sumimoto M. Stereoselective Synthesis of 1-Nitrobicyclo[3.1.0]hexanes and Fused Isoxazoline-N-oxides from Primary Nitro Compounds. J Org Chem 2012; 77:2236-45. [DOI: 10.1021/jo202489v] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Akio Kamimura
- Department of Applied Molecular
Bioscience, Graduate School of Medicine, Yamaguchi University, Ube 755-8611, Japan
| | - Ryota Takeuchi
- Department of Applied Molecular
Bioscience, Graduate School of Medicine, Yamaguchi University, Ube 755-8611, Japan
| | - Kosuke Ikeda
- Department of Applied Molecular
Bioscience, Graduate School of Medicine, Yamaguchi University, Ube 755-8611, Japan
| | - Takaaki Moriyama
- Department of Applied Molecular
Bioscience, Graduate School of Medicine, Yamaguchi University, Ube 755-8611, Japan
| | - Michinori Sumimoto
- Department of Material Chemistry,
Graduate School of Science and Engineering, Yamaguchi University, Ube 755-8611, Japan
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21
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Narhe BD, Sriramurthy V, Yadav VK. A smooth rearrangement of N-p-toluenesulfonyl 2-tert-butyldiphenylsilylmethyl-substituted azetidines into N-p-toluenesulfonyl 3-tert-butyldiphenylsilyl-substituted pyrrolidines. Org Biomol Chem 2012; 10:4390-9. [DOI: 10.1039/c2ob07140a] [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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22
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Gu Q, You SL. Desymmetrization of cyclohexadienones via cinchonine derived thiourea-catalyzed enantioselective aza-Michael reaction and total synthesis of (-)-Mesembrine. Chem Sci 2011. [DOI: 10.1039/c1sc00083g] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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23
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Lakhdar S, Terrier F, Vichard D, Berionni G, El Guesmi N, Goumont R, Boubaker T. The Diels-Alder reaction of 4,6-dinitrobenzofuroxan with 1-trimethylsilyloxybuta-1,3-diene: a case example of a stepwise cycloaddition. Chemistry 2010; 16:5681-90. [PMID: 20376824 DOI: 10.1002/chem.200903008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The reaction of 4,6-dinitrobenzofuroxan (DNBF) with 1-trimethylsilyloxybuta-1,3-diene (8) is shown to afford a mixture of [2+4] diastereomeric cycloadducts (10, 11) through stepwise addition-cyclization pathways. Zwitterionic intermediate sigma-adduct 9, which is involved in the processes, has been successfully characterized by (1)H and (13)C NMR spectroscopy and UV/visible spectrophotometry in acetonitrile. A kinetic study has been carried out in this solvent that revealed that the rate of formation of 9 nicely fits the three-parameter equation log k=s(E+N) developed by Mayr to describe the feasibility of nucleophile-electrophile combinations. This significantly adds to the NMR spectroscopic evidence that the overall cycloadditions take place through a stepwise mechanism. The reaction has also been studied in dichloromethane and toluene. In these less polar solvents, the stability of 9 is not sufficient to allow direct characterization by spectroscopic methods, but a kinetic investigation supports the view that stepwise processes are still operating. An informative comparison of our reaction with previous interactions firmly identified as prototype stepwise cycloadditions is made on the basis of the global electrophilicity index, omega, defined by Parr within the density functional theory, and highlighted by Domingo et al. as a powerful tool for understanding Diels-Alder reactions.
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Affiliation(s)
- Sami Lakhdar
- Institut Lavoisier de Versailles, UMR 8180, Université de Versailles, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France
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García Ruano J, Martín-Castro A, Tato F, Torrente E, Poveda A. Stereodivergent Quaternization of 2-Alkyl-2-p-tolylsulfinylacetonitriles: NMR Spectroscopic Evidence of Planar and Pyramidal Benzylic Carbanions. Chemistry 2010; 16:6317-25. [DOI: 10.1002/chem.200903521] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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25
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Burrell AJM, Watson L, Martin NG, Oram N, Coldham I. Synthesis of the core ring system of the stemona alkaloids by cascade condensation, cyclization, intramolecular cycloaddition. Org Biomol Chem 2010; 8:4530-2. [DOI: 10.1039/c0ob00408a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Denmark SE, Baiazitov RY, Nguyen ST. Tandem double intramolecular [4+2]/[3+2] cycloadditions of nitroalkenes: construction of the pentacyclic core structure of daphnilactone B. Tetrahedron 2009; 65:6535-6548. [PMID: 22180670 DOI: 10.1016/j.tet.2009.05.060] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
An asymmetric synthesis of the ABCD ring system of daphnilactone B is described. The synthesis features a tandem, double intramolecular, [4+2]/[3+2] cycloaddition of a highly functionalized, enantiomerically enriched nitroalkene to generate a pentacyclic nitroso acetal. The cycloaddition establishes six contiguous stereogenic centers including the critical CD ring junction that bears two quaternary stereogenic centers. Hydrogenolysis of the nitroso acetal followed by amide reduction and cyclization provided the AB rings. The methyl substituent on the A ring was installed in the correct configuration via hydrogenation of an exocyclic olefin in the final step.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, IL 61801, USA
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Burrell AJM, Coldham I, Watson L, Oram N, Pilgram CD, Martin NG. Stereoselective formation of fused tricyclic amines from acyclic aldehydes by a cascade process involving condensation, cyclization, and dipolar cycloaddition. J Org Chem 2009; 74:2290-300. [PMID: 18998734 DOI: 10.1021/jo8019913] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The preparation of tricyclic amines from acyclic precursors is described using a cascade of tandem reactions involving condensation of an aldehyde with a primary amine, cyclization (with displacement of a halide), and then in situ deprotonation or decarboxylation to give an azomethine ylide or nitrone followed by intramolecular dipolar cycloaddition. The methodology is straightforward, and the aldehyde precursors are prepared easily and quickly in high yield using nitrile alkylations followed by DIBAL-H reduction. The relative ease of reaction of various substrates with different tether lengths between the aldehyde and the halide or dipolarophile has been studied. Several primary amines including simple amino acids such as glycine, alanine, and phenylalanine and derivatives such as glycine ethyl ester and also hydroxylamine have been investigated. High yields are obtained in the formation of different tricyclic ring sizes; the dipolar cycloaddition necessarily creates a five-membered ring, and we have investigated the formation of five- and six-membered rings for the other two new ring sizes. In all cases, yields are high (except when using glycine when the tether to the terminal alkene dipolarophile leads to a six-membered ring), and most efficient is the formation of the tricyclic product in which all five-membered rings are formed. Examples with an alkyne as the dipolarophile were also successful. In all the reactions studied, the products are formed with complete regioselectivity and remarkably with complete stereoselectivity. The key step involves the formation of three new rings and potentially up to four new stereocenters in a single transformation. The power of the chemistry was demonstrated by the synthesis of the core ring systems of the alkaloids (+/-)-scandine and (+/-)-myrioneurinol and the total syntheses of the alkaloids (+/-)-aspidospermine, (+/-)-quebrachamine, and (+/-)-aspidospermidine.
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Affiliation(s)
- Adam J M Burrell
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
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28
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Ilardi EA, Isaacman MJ, Qin YC, Shelly SA, Zakarian A. Consecutive sigmatropic rearrangements in the enantioselective total synthesis of (−)-joubertinamine and (−)-mesembrine. Tetrahedron 2009. [DOI: 10.1016/j.tet.2008.10.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Guérard KC, Sabot C, Racicot L, Canesi S. Oxidative Friedel−Crafts Reaction and its Application to the Total Syntheses of Amaryllidaceae Alkaloids. J Org Chem 2009; 74:2039-45. [DOI: 10.1021/jo802728u] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kimiaka C. Guérard
- Laboratoire de Méthodologie et Synthèse de Produits Naturels, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal, H3C 3P8, Québec, Canada
| | - Cyrille Sabot
- Laboratoire de Méthodologie et Synthèse de Produits Naturels, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal, H3C 3P8, Québec, Canada
| | - Léanne Racicot
- Laboratoire de Méthodologie et Synthèse de Produits Naturels, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal, H3C 3P8, Québec, Canada
| | - Sylvain Canesi
- Laboratoire de Méthodologie et Synthèse de Produits Naturels, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal, H3C 3P8, Québec, Canada
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Denmark SE, Ares JJ. Stereoselective alkylations of chiral nitro imine and nitro hydrazone dianions. Synthesis of enantiomerically enriched 3-substituted 1-nitrocyclohexenes. J Org Chem 2008; 73:9647-56. [PMID: 18855478 PMCID: PMC3199965 DOI: 10.1021/jo801790r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dianions of chiral nitro imines (generated by a combination of LDA and s-BuLi) underwent diastereoselective alkylation with methyl, butyl, isopropyl, allyl, and methallyl iodides. In contrast to the behavior of simple metalloenamines, the most selective auxiliary contained no coordinating groups but did possess a large steric difference between the two substituents. The yield and selectivity of the alkylations were improved by the addition of HMPA or DMPU. The use of (S)-1-naphthylethylamine as the auxiliary afforded the R absolute configuration of the alkylation products. This stereochemical outcome could be rationalized by simple steric approach controlled alkylation in a conformationally fixed, internally coordinated dianion. A SAMP nitro hydrazone gave poorer yields and selectivities.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
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31
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Ishikawa T, Kudo K, Kuroyabu K, Uchida S, Kudoh T, Saito S. Domino Double Michael−Claisen Cyclizations: A Powerful General Tool for Introducing Quaternary Stereocenters at C(4) of Cyclohexane-1,3-diones and Total Synthesis of Diverse Families of Sterically Congested Alkaloids. J Org Chem 2008; 73:7498-508. [DOI: 10.1021/jo801316s] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Teruhiko Ishikawa
- Department of Medical and Bioengineering Science, Graduate School of Natural Science and Technology, Okayama University, Tsushima, Okayama, Japan 700-8530
| | - Kazuhiro Kudo
- Department of Medical and Bioengineering Science, Graduate School of Natural Science and Technology, Okayama University, Tsushima, Okayama, Japan 700-8530
| | - Ken Kuroyabu
- Department of Medical and Bioengineering Science, Graduate School of Natural Science and Technology, Okayama University, Tsushima, Okayama, Japan 700-8530
| | - Satoshi Uchida
- Department of Medical and Bioengineering Science, Graduate School of Natural Science and Technology, Okayama University, Tsushima, Okayama, Japan 700-8530
| | - Takayuki Kudoh
- Department of Medical and Bioengineering Science, Graduate School of Natural Science and Technology, Okayama University, Tsushima, Okayama, Japan 700-8530
| | - Seiki Saito
- Department of Medical and Bioengineering Science, Graduate School of Natural Science and Technology, Okayama University, Tsushima, Okayama, Japan 700-8530
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32
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Stecko S, Paśniczek K, Michel C, Milet A, Pérez S, Chmielewski M. A DFT study of 1,3-dipolar cycloaddition reactions of 5-membered cyclic nitrones with α,β-unsaturated lactones and with cyclic vinyl ethers: Part 1. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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33
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Coldham I, Burrell AJM, White LE, Adams H, Oram N. Highly efficient synthesis of tricyclic amines by a cyclization/cycloaddition cascade: total syntheses of aspidospermine, aspidospermidine, and quebrachamine. Angew Chem Int Ed Engl 2007; 46:6159-62. [PMID: 17623291 DOI: 10.1002/anie.200701943] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Iain Coldham
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK.
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Coldham I, Burrell A, White L, Adams H, Oram N. Highly Efficient Synthesis of Tricyclic Amines by a Cyclization/Cycloaddition Cascade: Total Syntheses of Aspidospermine, Aspidospermidine, and Quebrachamine. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200701943] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Denmark S, Cottell J. A Tandem, Nitroalkene Conjugate Addition/[3+2] Cycloaddition Approach to the Synthesis of the Pentacyclic Core of (±)-Scandine. Adv Synth Catal 2006. [DOI: 10.1002/adsc.200600301] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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36
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Bastida J, Lavilla R, Viladomat F. Chemical and biological aspects of Narcissus alkaloids. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2006; 63:87-179. [PMID: 17133715 PMCID: PMC7118783 DOI: 10.1016/s1099-4831(06)63003-4] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This chapter discusses the chemical and biological aspects of Narcissus alkaloids. Numerous alkaloids have been isolated from Narcissus speciesasaresult of the continuing search for novel alkaloids with pharmacological activity in the Amaryllidaceae family. The alkaloids isolated from this genus, classified in relation to the different skeleton types. The different Narcissus wild species and intersectional hybrids, grouped into subgenera and sections, with their corresponding alkaloids, arranged according to their ring system are listed. The biosynthetic pathways of Narcissus alkaloids includes: (1) enzymatic preparation of the precursors, (2) primary cyclization mechanisms, (3) enzymatic preparation of intermediates, (4) secondary cyclization, diversification, and restructuring. The chapter discusses proton nuclear magnetic resonance (1H NMR), carbon nuclear magnetic resonance (13C NMR), and mass spectrometry (MS) for Narcissus alkaloids. A list of the different Narcissus alkaloids, their spectroscopic properties, and literature with the most recent spectroscopic data is given. Several Narcissus extracts shows the following activities: antiviral, prophage induction, antibacterial, antifungal, antimalarial, insecticidal, cytotoxic, antitumor, antimitotic, antiplatelet, hypotensive, emetic, acetylcholine esterase inhibitory, antifertility, antinociceptive, chronotropic, pheromone, plant growth inhibitor, and allelopathic.
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Affiliation(s)
- Jaume Bastida
- Departament de Productes Naturals, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
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37
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Sawada T, Nakada M. Asymmetric Catalysis of Intramolecular Cyclopropanation of 5-Aryl-1-diazo-1-mesitylsulfonyl-5-hexen-2-ones. Adv Synth Catal 2005. [DOI: 10.1002/adsc.200505173] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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38
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Kulinkovich O. Synthetic Applications of Intermolecular Cyclopropanation of Carboxylic Esters with Dialkoxytitanacyclopropane Reagents. European J Org Chem 2004. [DOI: 10.1002/ejoc.200400234] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Oleg Kulinkovich
- Department of Chemistry, Belorussian State University, Fr. Skariny Av. 4, Minsk 220 050, Belarus, Fax: (internat.) + 7‐375‐(17)226‐4998
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39
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Denmark SE, Gomez L. Tandem double intramolecular [4+2]/[3+2] cycloadditions of nitroalkenes. The fused/bridged mode. J Org Chem 2004; 68:8015-24. [PMID: 14535778 DOI: 10.1021/jo034853w] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new class of tandem [4+2]/[3+2] cycloadditions of nitroalkenes is described in which both pericyclic processes are intramolecular. Two subclasses of intra [4+2]/intra [3+2] cycloadditions have been explored in which the dipolarophile is tethered at either C(5) or C(6) of the nitronate. For both families of precursors, the cycloadditions occur in good yield and are found to be highly regio- and stereoselective. This method converts linear polyenes to functionalized polycyclic systems bearing up to six stereogenic centers.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
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40
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41
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Padwa A, Heidelbaugh TM, Kuethe JT, McClure MS, Wang Q. Tandem Pummerer/Mannich cyclization cascade of alpha-sulfinylamides as a method to prepare aza-heterocycles. J Org Chem 2002; 67:5928-37. [PMID: 12182624 DOI: 10.1021/jo020083x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of alpha-sulfinylenamides was conveniently prepared by the condensation of a primary amine with a ketone, followed by reaction of the resulting imine with ethylsulfenylacetyl chloride and subsequent oxidation with sodium periodate. When treated with p-TsOH, cyclization occurred to produce fused isoquinoline lactams by a mechanism that involves an initial Pummerer reaction followed by a subsequent cyclization of the resulting N-acyliminium ion onto the tethered aromatic ring. The isolation of a single diastereomer was rationalized in terms of a Nazarov-type 4pi-electrocyclic reaction followed by pi-cyclization onto the least hindered side of the N-acyliminium ion. Another method that was used to generate the alpha-acylthionium ion intermediate involved the reaction of bis(ethylsulfenylacetyl)acetamides with dimethyl(methyl)thiosulfonium tetrafluoroborate (DMTSF). Treatment of several bis-ethylsulfenylenamides with DMTSF delivered novel spiro-heterocycles as single diastereomers in good yield by a related process. The convergency and stereochemical control associated with this cascade sequence make it particularly suited for the assembly of natural product scaffolds. Some preliminary studies were directed toward both mesembrine and deethylibophyllidine. When the model Z-enamido sulfoxide 33 was heated with p-TsOH, a 80% yield of tosylate 34 was obtained as a single diastereomer. In this case, the carbocation intermediate derived from cyclization onto the terminal pi-bond was trapped with p-TsOH from the least hindered face, opposite the angular carbomethoxy and methyl groups. Related cyclization cascades were also found to occur with systems containing tethered indole rings.
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Affiliation(s)
- Albert Padwa
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
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42
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The Diels–Alder reactivity of nitrobenzofuroxans: mono- and di-adducts of isoprene and 2,3-dimethylbutadiene. New convenient precursors to naphtho- and phenanthreno-furoxanic and -furazanic structures. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)00236-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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43
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Kulkarni MG, Rasne RM, Davawala SI, Doke AK. Allyl vinyl ethers via Wittig olefination: a short and efficient synthesis of (±)-mesembrine. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00227-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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44
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45
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Denmark SE, Gomez L. Tandem double intramolecular [4 + 2]/[3 + 2] cycloadditions of nitroalkenes. Org Lett 2001; 3:2907-10. [PMID: 11529787 DOI: 10.1021/ol016385n] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text]. A new class of tandem [4 + 2]/[3 + 2] cycloadditions of nitroalkenes is described in which both pericyclic processes are intramolecular. Two subclasses of intra [4 + 2]/intra [3 + 2] cycloadditions have been explored in which the dipolarophile is tethered at either C(5) or C(6) of the nitronate. For both families of precursors, the cycloadditions occur in good yield and are found to be highly regio- and stereoselective. This method converts linear polyenes to functionalized polycyclic systems bearing up to six stereogenic centers.
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Affiliation(s)
- S E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, 61801.
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46
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Giomi D, Turchi S, Danesi A, Faggi C. 4-Nitroisoxazoles as nitroalkene heterodienes: diastereoselective synthesis of spiro tricyclic nitroso acetals by thermal reactions with ethyl vinyl ether. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00310-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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47
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Dual behavior of 4-aza-6-nitrobenzofuroxan. A powerful electrophile in hydration and sigma-complex formation and a potential dienophile or heterodiene in diels-alder type reactions. J Org Chem 2000; 65:7391-8. [PMID: 11076595 DOI: 10.1021/jo0005114] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In investigating the reactivities of aza analogues of super-electrophile 4,6-dinitrobenzofuroxan (DNBF, 1), we have found that the nitro-substituted pyridofuroxan 2 gives a remarkably stable hydrate 3 in aqueous solution (as evidenced by the requirement of ca. 50% H(2)SO(4) (H(0) approximately -3) for complete recovery of 2). The equilibrium constant K(H)()2(O) for hydration of 2 is estimated to be >/= 100, being comparable only with the K(H)()2(O) values reported for hydration of highly activated neutral polyazaaromatics such as 2- and 6-hydroxypteridines or 7-azapteridine. Interestingly, the NH group of 3 undergoes ionization at rather low pH (p = 5.79), affording an anionic hydroxy sigma-adduct 4 which is thermodynamically 10(8) times more stable than the related sigma-adduct of pteridine. The experimental evidence is that 4 is slightly more stable than the hydroxy sigma-adduct of DNBF, indicating not only that 2 ranks among the most electrophilic heteroaromatics known to date but also than an aza group may in fact be as efficient as a nitro group in promoting sigma-complex formation. 2 is also found to be a versatile Diels-Alder reagent, as a result of the low aromatic character of its six-membered ring. Upon treatment of 2 with cyclopentadiene and 2,3-dimethylbutadiene, various reactivity patterns have been observed. These led to different cycloadducts arising from normal as well as inverse electron-demand condensations involving the pyridine ring as the dienophile or the heterodiene contributor. Altogether, the results reveal major differences between the reactivity of 2 and that of DNBF, with in particular a remarkable tendency of the pyridofuroxan adducts to undergo covalent hydration, resulting in the formation of stable carbinolamines. Also noteworthy is the characterization of a diadduct which results from a Diels-Alder trapping of the o-dinitroso intermediate involved in the exchange of the 1-oxide and 3-oxide tautomers of 2.
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48
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Hong JH, Gao MY, Choi Y, Cheng YC, Schinazi RF, Chu CK. Synthesis of novel 3'-C-methyl-apionucleosides: an asymmetric construction of a quaternary carbon by Claisen rearrangement. Carbohydr Res 2000; 328:37-48. [PMID: 11005574 DOI: 10.1016/s0008-6215(00)00005-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of 2,3-dideoxy-3-C-(hydroxymethyl)-3-C-methyl-D-glycero-tetrofuranosyl++ + nucleosides was accomplished in high enatiomeric purity (98.5% ee) via [3,3]-sigmatropic Claisen rearrangement of (E)(S)-5-benzyloxy-1-tert-butyldimethylsilanyloxy-4-methyl-pent-3- en-2-ol prepared from 2,3-O-isopropylidene-D-glyceraldehyde. The synthesized nucleosides were assayed against human immunodeficiency virus (HIV) and hepatitis B virus in human peripheral blood mononuclear (PBM) and 2.2.15 cells, respectively. 6-Amino-9-[2,3-dideoxy-3-C-(hydroxymethyl)-3-C-methyl-beta-D-glycero- tetrofuranosyl]-2-fluoropurine shows moderate antiviral activity (EC50 = 2.55 microM) against HIV-1 strains and 6-amino-9-[3-deoxy-3-C-(hydroxymethyl)-3-methyl-alpha-D-glycero-tetro furanosyl]-2-fluoropurine exhibits potent anti-HIV activity (EC50 = 0.073 microM) with significant cytotoxicity (IC50 = 1.0 microM).
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Affiliation(s)
- J H Hong
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens 30602, USA
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49
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Abstract
Highly efficient and selective syntheses of the title compounds are described. The cornerstone of the synthetic plan is the tandem inter [4 + 2]/inter [3 + 2] cycloaddition process. These syntheses differ from previous applications of this strategy in that they incorporate an alkylation in the hydrogenolysis step to close the second ring of the azabicyclic systems. Notable features of the sequence are (1) the highly regio- and stereoselective [3 + 2] cycloaddition of nitronate 15 with siloxymethyl (Z)-beta-silylvinyl ketone (Z)-22b and (2) the highly selective reduction of the resulting ketone 24a with L-Selectride. A single-crystal X-ray structure analysis of synthetic (-)-7-epiaustraline confirmed that the targeted structure was successfully synthesized. This stimulated a reexamination of the structural assignment of the natural product. (-)-1-Epicastanospermine was synthesized in four steps from the common intermediate 27a. The absolute configuration of (-)-1-epicastanospermine was assured by single-crystal X-ray structure analysis of intermediate (-)-27a. Thus, the sign of the optical rotation had to be revised. The overall efficiency of these syntheses were 9 steps and 23% yield for (-)-7-epiaustraline and 10 steps and 20% yield for (-)-1-epicastanospermine
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Affiliation(s)
- S E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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50
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KANEMASA S. Stereo- and Regio-Control of 1, 3-Dipolar Cycloaddition Reactions by the Aid of Lewis Acid Catalysts—Nitrone and aci-Nitro Compound Cycloadditions—. ACTA ACUST UNITED AC 2000. [DOI: 10.1246/nikkashi.2000.155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Shuji KANEMASA
- Institute of Advanced Material Study, Kyushu University; 6-1 Kasugakoen, Kasuga-shi 816-8580 Japan
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