1
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Krueger R, Moeller KD. Capitalizing on Mediated Electrolyses for the Construction of Complex, Addressable Molecular Surfaces. J Org Chem 2021; 86:15847-15865. [PMID: 34617752 PMCID: PMC8802379 DOI: 10.1021/acs.joc.1c01609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Synthetic organic chemists are beginning to exploit electrochemical methods in increasingly creative ways. This is leading to a surge in productivity that is only now starting to take advantage of the full-potential of electrochemistry for accessing new structures in novel, more efficient ways. In this perspective, we provide insight into the potential of electrochemistry as a synthetic tool gained through studies of both direct anodic oxidation reactions and more recent indirect methods, and highlight how the development of new electrochemical methods can expand the nature of synthetic problems our community can tackle.
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Affiliation(s)
- Ruby Krueger
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
| | - Kevin D. Moeller
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
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2
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Traceless Solid-Phase Synthesis of [6,7,8 + 5,6,7]-Fused Molecular Frameworks. Molecules 2018; 23:molecules23051090. [PMID: 29734722 PMCID: PMC6102595 DOI: 10.3390/molecules23051090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 04/30/2018] [Accepted: 05/02/2018] [Indexed: 11/17/2022] Open
Abstract
We report two synthetic strategies for traceless solid-phase synthesis of molecular scaffolds comprising 6- to 8-membered rings fused with 5- to 7-membered rings. Traceless synthesis facilitated preparation of target molecules without any trace of polymer-supported linkers. The cyclization proceeded via acid-mediated tandem N-acylium ion formation followed by the nucleophilic addition of O- and C-nucleophiles. The presented synthetic strategy enabled, through the use of simple building blocks without any conformational preferences, the evaluation of the predisposition of different combinations of ring sizes to form fused ring molecular scaffolds. Compounds with any combination of [6,7 + 5,6,7] ring sizes were accessible with excellent crude purity. The 8-membered cyclic iminium was successfully fused only with the 5-membered cycle and larger fused ring systems were not formed, probably due to their instability.
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3
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Chiha S, Soicke A, Barone M, Müller M, Bruns J, Opitz R, Neudörfl JM, Kühne R, Schmalz HG. Design and Synthesis of Building Blocks for PPII-Helix Secondary-Structure Mimetics: A Stereoselective Entry to 4-Substituted 5-Vinylprolines. European J Org Chem 2017. [DOI: 10.1002/ejoc.201701584] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Slim Chiha
- Department of Chemistry; University of Cologne; Greinstrasse 4 50939 Cologne Germany
| | - Arne Soicke
- Department of Chemistry; University of Cologne; Greinstrasse 4 50939 Cologne Germany
| | - Matthias Barone
- Campus BerlinBuch; Leibniz-Institut für Molekulare Pharmakologie (FMP); 13125 Berlin Germany
| | - Matthias Müller
- Campus BerlinBuch; Leibniz-Institut für Molekulare Pharmakologie (FMP); 13125 Berlin Germany
| | - Judith Bruns
- Department of Chemistry; University of Cologne; Greinstrasse 4 50939 Cologne Germany
| | - Robert Opitz
- Campus BerlinBuch; Leibniz-Institut für Molekulare Pharmakologie (FMP); 13125 Berlin Germany
| | - Jörg-Martin Neudörfl
- Department of Chemistry; University of Cologne; Greinstrasse 4 50939 Cologne Germany
| | - Ronald Kühne
- Campus BerlinBuch; Leibniz-Institut für Molekulare Pharmakologie (FMP); 13125 Berlin Germany
| | - Hans-Günther Schmalz
- Department of Chemistry; University of Cologne; Greinstrasse 4 50939 Cologne Germany
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4
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Kaplaneris N, Spyropoulos C, Kokotou MG, Kokotos CG. Enantioselective Organocatalytic Synthesis of 2-Oxopiperazines from Aldehydes: Identification of the Elusive Epoxy Lactone Intermediate. Org Lett 2016; 18:5800-5803. [PMID: 27792345 DOI: 10.1021/acs.orglett.6b02699] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An organocatalytic linchpin catalysis approach was envisaged to convert simple aldehydes into enantioenriched 2-oxopiperazines. A four-step reaction sequence (chlorination, oxidation, substitution, and cyclization) was developed and led to different substitution patterns in high yields and selectivities. The reaction mechanism was studied, and the previously elusive epoxy lactone intermediate was identified by HRMS.
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Affiliation(s)
- Nikolaos Kaplaneris
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens 15771, Greece
| | - Constantinos Spyropoulos
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens 15771, Greece
| | - Maroula G Kokotou
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens 15771, Greece
| | - Christoforos G Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens 15771, Greece
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5
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Trost BM, Donckele EJ, Thaisrivongs DA, Osipov M, Masters JT. A New Class of Non-C2-Symmetric Ligands for Oxidative and Redox-Neutral Palladium-Catalyzed Asymmetric Allylic Alkylations of 1,3-Diketones. J Am Chem Soc 2015; 137:2776-84. [DOI: 10.1021/jacs.5b00786] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Barry M. Trost
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Etienne J. Donckele
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - David A. Thaisrivongs
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Maksim Osipov
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - James T. Masters
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
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6
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Perryman MS, Earl MWM, Greatorex S, Clarkson GJ, Fox DJ. Synthesis of 1- and 4-substituted piperazin-2-ones via Jocic-type reactions with N-substituted diamines. Org Biomol Chem 2015; 13:2360-5. [DOI: 10.1039/c4ob02311k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Enantiomerically-enriched trichloromethyl-containing alcohols are transformed regioselectively into enantiomerically-enriched 1-substituted piperazinones by modified Jocic reactions.
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Affiliation(s)
| | | | - Sam Greatorex
- Department of Chemistry
- University of Warwick
- Coventry
- U.K
| | | | - David J. Fox
- Department of Chemistry
- University of Warwick
- Coventry
- U.K
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7
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Jones AM, Banks CE. The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon-carbon bond formation via electrogenerated N-acyliminium ions. Beilstein J Org Chem 2014; 10:3056-72. [PMID: 25670975 PMCID: PMC4311756 DOI: 10.3762/bjoc.10.323] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 12/05/2014] [Indexed: 11/23/2022] Open
Abstract
N-acyliminium ions are useful reactive synthetic intermediates in a variety of important carbon–carbon bond forming and cyclisation strategies in organic chemistry. The advent of an electrochemical anodic oxidation of unfunctionalised amides, more commonly known as the Shono oxidation, has provided a complementary route to the C–H activation of low reactivity intermediates. In this article, containing over 100 references, we highlight the development of the Shono-type oxidations from the original direct electrolysis methods, to the use of electroauxiliaries before arriving at indirect electrolysis methodologies. We also highlight new technologies and techniques applied to this area of electrosynthesis. We conclude with the use of this electrosynthetic approach to challenging syntheses of natural products and other complex structures for biological evaluation discussing recent technological developments in electroorganic techniques and future directions.
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Affiliation(s)
- Alan M Jones
- Manchester Metropolitan University, Faculty of Science and Engineering, School of Science and the Environment, Division of Chemistry and Environmental Science, John Dalton Building, Chester Street, Manchester, M1 5GD, UK
| | - Craig E Banks
- Manchester Metropolitan University, Faculty of Science and Engineering, School of Science and the Environment, Division of Chemistry and Environmental Science, John Dalton Building, Chester Street, Manchester, M1 5GD, UK
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8
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Francke R. Recent advances in the electrochemical construction of heterocycles. Beilstein J Org Chem 2014; 10:2858-73. [PMID: 25550752 PMCID: PMC4273298 DOI: 10.3762/bjoc.10.303] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 11/18/2014] [Indexed: 01/09/2023] Open
Abstract
Due to the fact that the major portion of pharmaceuticals and agrochemicals contains heterocyclic units and since the overall number of commercially used heterocyclic compounds is steadily growing, heterocyclic chemistry remains in the focus of the synthetic community. Enormous efforts have been made in the last decades in order to render the production of such compounds more selective and efficient. However, most of the conventional methods for the construction of heterocyclic cores still involve the use of strong acids or bases, the operation at elevated temperatures and/or the use of expensive catalysts and reagents. In this regard, electrosynthesis can provide a milder and more environmentally benign alternative. In fact, numerous examples for the electrochemical construction of heterocycles have been reported in recent years. These cases demonstrate that ring formation can be achieved efficiently under ambient conditions without the use of additional reagents. In order to account for the recent developments in this field, a selection of representative reactions is presented and discussed in this review.
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Affiliation(s)
- Robert Francke
- Department of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany
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9
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M. Beauchemin A, Das Neves N, Raymond M. Expedient Synthesis of 2-Oxopiperazines Using a SN2 / Cope-Type Hydroamination Sequence. HETEROCYCLES 2014. [DOI: 10.3987/com-13-s(s)18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Slama S, Elemine BO, Besbes R. Convenient Synthesis of 1,2-Diamines from β-Chloro Amines: Precursors of New Substituted Piperazin-2-ones. SYNTHETIC COMMUN 2013. [DOI: 10.1080/00397911.2012.700080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Soumaya Slama
- a Faculty of Sciences, Department of Chemistry , Laboratory of Analytical Chemistry and Electrochemistry , Tunis , Tunisia
| | - Brahim Ould Elemine
- a Faculty of Sciences, Department of Chemistry , Laboratory of Analytical Chemistry and Electrochemistry , Tunis , Tunisia
| | - Rafâa Besbes
- a Faculty of Sciences, Department of Chemistry , Laboratory of Analytical Chemistry and Electrochemistry , Tunis , Tunisia
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11
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Gabrielli S, Ballini R, Palmieri A. β-Nitroacrylates as key building blocks for the synthesis of alkyl 3-substituted 5-oxopiperazine-2-carboxylates under fully heterogeneous conditions. MONATSHEFTE FUR CHEMIE 2013. [DOI: 10.1007/s00706-012-0895-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Trost BM, Thaisrivongs DA, Donckele EJ. Palladium-Catalyzed Enantioselective Allylic Alkylations through C-H Activation. Angew Chem Int Ed Engl 2012; 52:1523-6. [DOI: 10.1002/anie.201207870] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 11/27/2012] [Indexed: 11/06/2022]
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13
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Trost BM, Thaisrivongs DA, Donckele EJ. Palladium-Catalyzed Enantioselective Allylic Alkylations through C-H Activation. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201207870] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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An efficient entry to highly substituted chiral 2-oxopiperazines from α-amino acids via iodocyclization. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.09.109] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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16
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Fatás P, Gil AM, Calaza MI, Jiménez AI, Cativiela C. Access to Enantiomerically Pure cis
- and trans
-β-Phenylproline by High-Performance Liquid Chromatography Resolution. Chirality 2012; 24:1082-91. [DOI: 10.1002/chir.22101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 07/04/2012] [Indexed: 02/03/2023]
Affiliation(s)
- Paola Fatás
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); CSIC-Universidad de Zaragoza; 50009 Zaragoza Spain
| | - Ana M. Gil
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); CSIC-Universidad de Zaragoza; 50009 Zaragoza Spain
| | - M. Isabel Calaza
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); CSIC-Universidad de Zaragoza; 50009 Zaragoza Spain
| | - Ana I. Jiménez
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); CSIC-Universidad de Zaragoza; 50009 Zaragoza Spain
| | - Carlos Cativiela
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); CSIC-Universidad de Zaragoza; 50009 Zaragoza Spain
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17
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Mohite AR, Bhat RG. Enantiopure Synthesis of Side Chain-Modified α-Amino Acids and 5-cis-Alkylprolines. J Org Chem 2012; 77:5423-8. [DOI: 10.1021/jo300653u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amar R. Mohite
- Department of Chemistry, Mendeleev Block, Indian Institute of Science Education and Research (IISER),
Pune, Maharashtra, 411008, India
| | - Ramakrishna G. Bhat
- Department of Chemistry, Mendeleev Block, Indian Institute of Science Education and Research (IISER),
Pune, Maharashtra, 411008, India
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18
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Fatás P, Jiménez AI, Calaza MI, Cativiela C. β-Phenylproline: the high β-turn forming propensity of proline combined with an aromatic side chain. Org Biomol Chem 2012; 10:640-51. [DOI: 10.1039/c1ob06561k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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19
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Louafi F, Hurvois JP, Chibani A, Roisnel T. Synthesis of tetrahydroisoquinoline alkaloids via anodic cyanation as the key step. J Org Chem 2010; 75:5721-4. [PMID: 20704442 DOI: 10.1021/jo100714y] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a new route to tetrahydroisoquinoline (THIQ) alkaloids involving the alkylation of alpha-aminonitrile 2 as a key step. The latter compound was prepared by anodic cyanation of the corresponding tertiary amine 1. Reductive decyanation of alpha-aminonitriles 6a-c proceeded diastereoselectively (up to 95% de) to deliver the C1-substituted alkaloids precursors 9a-c. The syntheses of (+/-)-carnegine, (+/-)-norlaudanosine, and (+/-)-O,O-dimethylcoclaurine have been achieved.
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Affiliation(s)
- Fadila Louafi
- Département de Chimie, Faculté des Sciences Exactes,Université Mentouri de Constantine, Route de Ain El Bey,25000 Constantine, Algérie
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20
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Xu HC, Moeller KD. Intramolecular anodic olefin coupling reactions and the synthesis of cyclic amines. J Am Chem Soc 2010; 132:2839-44. [PMID: 20131795 PMCID: PMC3950632 DOI: 10.1021/ja910586v] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Anodic olefin coupling reactions using a tosylamine trapping group have been studied. The cyclizations are favored by the use of a less-polar radical cation and more basic reaction conditions. The most significant factor for obtaining good yields of cyclic product is the use of the more basic reaction conditions. However, a number of factors including the nature of both the solvent and the electrolyte used can influence the yield of the cyclizations. The cyclizations allow for the rapid synthesis of both substituted proline and pipecolic acid type derivatives.
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Affiliation(s)
- Hai-Chao Xu
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Kevin D. Moeller
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
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21
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Affiliation(s)
- Petra Tošovská
- Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003
| | - Paramjit S. Arora
- Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003
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22
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De Risi C, Pelà M, Pollini GP, Trapella C, Zanirato V. Mastering chiral substituted 2-oxopiperazines. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.tetasy.2010.02.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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23
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Okuda K, Hirota T, Kingery DA, Nagasawa H. Synthesis of a Fluorine-Substituted Puromycin Derivative for Brønsted Studies of Ribosomal-Catalyzed Peptide Bond Formation. J Org Chem 2009; 74:2609-12. [DOI: 10.1021/jo802611t] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kensuke Okuda
- Gifu Pharmaceutical University, Gifu 502-8585, Japan, Faculty of Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan, and Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114
| | - Takashi Hirota
- Gifu Pharmaceutical University, Gifu 502-8585, Japan, Faculty of Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan, and Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114
| | - David A. Kingery
- Gifu Pharmaceutical University, Gifu 502-8585, Japan, Faculty of Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan, and Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114
| | - Hideko Nagasawa
- Gifu Pharmaceutical University, Gifu 502-8585, Japan, Faculty of Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan, and Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114
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24
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Dinsmore CJ, Beshore DC. SYNTHESES AND TRANSFORMATIONS OF PIPERAZINONE RINGS. A REVIEW. ORG PREP PROCED INT 2009. [DOI: 10.1080/00304940209458075] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Christopher J. Dinsmore
- a Department of Medicinal Chemistry , Merck Research Laboratories , West Point, PA, 19486, USA
| | - Douglas C. Beshore
- a Department of Medicinal Chemistry , Merck Research Laboratories , West Point, PA, 19486, USA
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25
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Alladoum J, Roland S, Vrancken E, Mangeney P, Kadouri-Puchot C. Short Enantioselective Syntheses of trans-5-Alkylprolines from New Functionalized Amino Alcohols. J Org Chem 2008; 73:9771-4. [DOI: 10.1021/jo8014243] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeanne Alladoum
- Université Pierre et Marie Curie-Paris 6, Laboratoire de Chimie Organique UMR 7611, Institut de Chimie Moléculaire FR 2769, 4 place Jussieu, case courrier 47, 75005 Paris, France
| | - Sylvain Roland
- Université Pierre et Marie Curie-Paris 6, Laboratoire de Chimie Organique UMR 7611, Institut de Chimie Moléculaire FR 2769, 4 place Jussieu, case courrier 47, 75005 Paris, France
| | - Emmanuel Vrancken
- Université Pierre et Marie Curie-Paris 6, Laboratoire de Chimie Organique UMR 7611, Institut de Chimie Moléculaire FR 2769, 4 place Jussieu, case courrier 47, 75005 Paris, France
| | - Pierre Mangeney
- Université Pierre et Marie Curie-Paris 6, Laboratoire de Chimie Organique UMR 7611, Institut de Chimie Moléculaire FR 2769, 4 place Jussieu, case courrier 47, 75005 Paris, France
| | - Catherine Kadouri-Puchot
- Université Pierre et Marie Curie-Paris 6, Laboratoire de Chimie Organique UMR 7611, Institut de Chimie Moléculaire FR 2769, 4 place Jussieu, case courrier 47, 75005 Paris, France
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26
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New efficient enantioselective synthesis of 2-oxopiperazines: a practical access to chiral 3-substituted 2-oxopiperazines. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.06.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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27
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Kesselring D, Maurer K, Moeller KD. Building Addressable Libraries: Site-Selective Formation of an N-Acyliminium Ion Intermediate. Org Lett 2008; 10:2501-4. [DOI: 10.1021/ol8007827] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David Kesselring
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and CombiMatrix Corporation, 6500 Harbor Heights Parkway, Suite 301, Mukilteo, Washington 98275
| | - Karl Maurer
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and CombiMatrix Corporation, 6500 Harbor Heights Parkway, Suite 301, Mukilteo, Washington 98275
| | - Kevin D. Moeller
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and CombiMatrix Corporation, 6500 Harbor Heights Parkway, Suite 301, Mukilteo, Washington 98275
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28
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Vaswani RG, Chamberlin AR. Stereocontrolled total synthesis of (--)-kaitocephalin. J Org Chem 2008; 73:1661-81. [PMID: 18225916 DOI: 10.1021/jo702329z] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper describes the successful implementation of a stereocontrolled strategy for the total chemical synthesis of the pyrrolidine-based alkaloid (--)-kaitocephalin. This scalable synthetic route profits from the strategic utilization of substrate-controlled manipulations for the iterative installation of the requisite stereogenic centers. The key transformations include a diastereoselective modified Claisen condensation, a chemo- and diastereoselective reduction of a beta-keto ester, and the substrate-directed hydrogenation of a dehydroamino ester derivative. During the course of our investigations, an interesting stereoconvergent cyclization reaction was discovered for the efficient assembly of the kaitocephalin 2,2,5-trisubstituted pyrrolidine core.
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Affiliation(s)
- Rishi G Vaswani
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, USA
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29
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Reginato G, Di Credico B, Andreotti D, Mingardi A, Paio A, Donati D. A new versatile and diastereoselective synthesis of polysubstituted 2-oxopiperazines from naturally occurring amino acids. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.10.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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30
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Trabocchi A, Scarpi D, Guarna A. Structural diversity of bicyclic amino acids. Amino Acids 2007; 34:1-24. [PMID: 17701095 DOI: 10.1007/s00726-007-0588-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Accepted: 07/12/2007] [Indexed: 10/23/2022]
Abstract
Over the years biomedical research has been constantly oriented towards the development of new therapeutics based on bioactive peptides and their analogues. In particular, the generation of compounds having structures and functions similar to bioactive peptides, named "peptidomimetics", raised much interest among organic and medicinal chemists due to the possibility by using such compounds to improve both potency and stability of peptidic lead compounds. In the context of this research area, unnatural amino acids are of great interest in drug discovery, and their use as new building blocks for the development of peptidomimetics with high diversity level and possessing high-ordered structures is of special interest. In particular, medicinal chemistry has taken advantage of the use of amino acid homologues and of cyclic and polycyclic templates to introduce elements of diversity for the generation of new molecules as drug candidates. Bicyclic amino acids have been developed as reverse turn mimetics and dipeptide isosteres, and the constraint imposed by their structures has been reported as a tool for controlling the conformational preferences of modified peptides. Moreover, synthetic efforts have been driven to the generation of diverse structures based on the modulation of ring size and scaffold decoration by suitable functional groups. Herein is reported an overview of different classes of bicyclic amino acids, taking into account the strategies to achieve structurally diverse templates, and some implications in medicinal chemistry are also disclosed.
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Affiliation(s)
- A Trabocchi
- Dipartimento di Chimica Organica Ugo Schiff, Università degli Studi di Firenze, Polo Scientifico e Tecnologico, Sesto Fiorentino, Firenze, Italy.
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31
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Lee SC, Park SB. Practical Solid-Phase Parallel Synthesis of Δ5-2-Oxopiperazines via N-Acyliminium Ion Cyclization. ACTA ACUST UNITED AC 2007; 9:828-35. [PMID: 17592879 DOI: 10.1021/cc0700492] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A practical solid-phase strategy for the synthesis of Delta(5)-2-oxopiperazines via N-acyliminium ion cyclization has been developed. A key step in the library synthesis is tandem acidolytic cleavage with subsequent in situ iminium formation, followed by stable enamide transformation. This approach is exemplified by the preparation of a 192-member pilot library using bromoacetal resins without further purification.
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Affiliation(s)
- Sung-Chan Lee
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea
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32
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Kumar I, Rode CV. Efficient Synthesis of Fused 1,2,3-Triazolo-δ-lactams Using Huisgen [3 + 2] Dipolar Cycloaddition “Click-chemistry” in Water. CHEM LETT 2007. [DOI: 10.1246/cl.2007.592] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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33
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Bittermann H, Böckler F, Einsiedel J, Gmeiner P. A Highly Practical RCM Approach towards a Molecular Building Kit of Spirocyclic Reverse Turn Mimics. Chemistry 2006; 12:6315-22. [PMID: 16729342 DOI: 10.1002/chem.200600432] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The development of privileged molecular scaffolds efficiently mimicking reverse turn motifs and thus increasing both binding and selectivity and enabling the elucidation of the bioactive conformation of a natural peptide has attracted remarkable interest. The frequent occurrence of proline in various turn patterns initiated the design of proline-based reverse turn mimetics. As a structural hybridization of a highly potent type VI beta-turn inducer 1 with saturated spirocyclic lactams 3 efficiently mimicking type II beta turns, we developed a versatile synthetic route towards unsaturated spirocyclic lactams of type 2, when Seebach's self-reproduction of chirality methodology was combined with a peptide coupling reaction and Grubbs' ring-closing metathesis. By this means, a variety of model peptides with six- up to nine-membered lactam rings were accessible following a uniform pathway. Introduction of suitably protected templates into solid-phase peptide synthesis gave rise to unsaturated spirocyclic analogues of the naturally occurring neuropeptide neurotensin. Spectroscopic investigations as well as DFT calculations on a high level of theory revealed a remarkable dependence of the reverse-turn inducing potency on the ring size. While the secondary structure of the unsaturated spirocyclic epsilon-lactam 12 closely agrees with the reference gamma-lactam 3 a, the unsaturated delta-lactam 11 serves as an extraordinarily potent beta-turn inducer which is even superior to beta-lactams of type 3 b. The eight-membered unsaturated spirocyclic lactam 13 adopts a conformation almost ideally matching the prerequisites for a canonical type II beta turn with the highest stability of the whole series. In contrast, the nine-membered spirolactam 14 represents a scaffold with a high conformational flexibility.
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Affiliation(s)
- Holger Bittermann
- Department of Medicinal Chemistry, Friedrich Alexander University Erlangen-Nürnberg, Schuhstrasse 19, 91052 Erlangen, Germany
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34
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Prenzel AHGP, Deppermann N, Maison W. Azabicycloalkenes as Synthetic Intermediates: Application to the Preparation of Diazabicycloalkane Scaffolds. Org Lett 2006; 8:1681-4. [PMID: 16597140 DOI: 10.1021/ol060287q] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] A general method to synthesize bicyclic dipeptide mimetics is reported. Key intermediates are azabicycloalkenes 9 and 17, which are prepared via Diels-Alder reactions and subsequent mild deprotection. These unsaturated bicyclic heterocycles are versatile intermediates for different dipeptide mimetics of the aza- and diazabicycloalkane type, which is demonstrated by the synthesis of diazabicycloalkanes 11 and 19 in only 3-6 steps and good overall yield.
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Affiliation(s)
- Alexander H G P Prenzel
- Institut für Organische Chemie, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
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35
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Grohs DC, Maison W. An improved cyclization protocol for the synthesis of diazabicyclo[4.3.0]alkanes. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.04.082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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36
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Grohs DC, Maison W. Synthesis of modular dipeptide mimetics on the basis of diazabicycloalkanes and derivatives thereof with sulphur containing side chains. Amino Acids 2005; 29:131-8. [PMID: 15864721 DOI: 10.1007/s00726-005-0182-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Accepted: 01/24/2005] [Indexed: 11/30/2022]
Abstract
We present the synthesis of new modular dipeptide mimetics based on diazabicycloalkane backbones. These diazabicycloalkanes are ligands for the prostate specific membrane antigen (PSMA), a well known tumor marker. Our previously described synthetic route to enantiomerically pure diazabicycloalkanes is extended to yield polyfunctional diazabicycloalkanes with a modular character using a new ring closing methodology. This, finally, allows us to attach linker moieties to different positions of the diazabicycloalkane scaffold providing conjugation sites to other functional molecules such as markers or cytostatic compounds. Furthermore, successful synthesis of sulphur-containing dipeptide analogues as for example CysX(AA)- or HCysX(AA)-mimetics on the basis of diazabicycloalkanes is described.
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Affiliation(s)
- D C Grohs
- Institut für Organische Chemie, Universität Hamburg, Hamburg, Germany
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37
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Pawar VG, De Borggraeve WM, Maes V, Tourwé DA, Compernolle F, Hoornaert GJ. Synthesis of sidechain adapted β-turn mimics for modifying the C-terminus of substance P. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.01.056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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38
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Aggarwal VK, Astle CJ, Iding H, Wirz B, Rogers-Evans M. Separation of pyrrolidine allylation products by diastereoselective enzymatic ester hydrolysis. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2004.12.062] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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39
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Franceschini N, Sonnet P, Guillaume D. Simple, versatile and highly diastereoselective synthesis of 1,3,4-trisubstituted-2-oxopiperazine-containing peptidomimetic precursors. Org Biomol Chem 2005; 3:787-93. [PMID: 15731863 DOI: 10.1039/b416162a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The selective O-deprotection of (1'S)-4-(tert-butoxycarbonyl)-1-[1'-phenylmethyloxymethyl-2'-[(tert-butyldimethylsilyl)oxy]ethyl]-2-oxopiperazine furnished an enantiomerically pure alcohol whose regio- and diastereoselective C3-alkylation yielded either (3R)- or (3S)-1,3,4-trisubstituted-2-oxopiperazines in high diastereomeric purity. These derivatives were efficiently transformed into (1'R)- or (1'S)-peptide templates utilizable to prepare peptidomimetics. This method provides easy access to each 1,3,4-trisubstituted-2-oxopiperazine diastereomer and facilitates, through the large choice of substituents at the 3-position together with the chemistry that can be performed on the N1 substituent, the preparation of a large number of diastereomerically pure constrained peptidomimetics from a single precursor.
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Affiliation(s)
- Nicolas Franceschini
- Laboratoire de Chimie Thérapeutique, EA 2629, 1 Rue des Louvels, 80000, Amiens, France
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40
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Sun H, Moeller KD. Building functionalized peptidomimetics: new electroauxiliaries and the use of a chemical oxidant for introducing N-acyliminium ions into peptides. Org Lett 2003; 5:3189-92. [PMID: 12943384 DOI: 10.1021/ol034872s] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The removal of electroauxiliaries from peptide substrates with chemical oxidants has been examined as a method for inserting N-acyliminium ions into the peptides. To this end, it was found that both 4-methoxyphenyldimethylsilyl and 2,4-dimethoxyphenyldimethylsilyl electroauxiliaries were readily cleaved with the use of ceric ammonium nitrate. Of the two groups, the 2,4-dimethoxyphenyldimethylsilyl electroauxiliary was the most labile under the oxidative conditions. The oxidation reactions were shown to be compatible with the use of a solid-phase substrate.
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Affiliation(s)
- Haizhou Sun
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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41
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Bencsik JR, Kercher T, O'Sullivan M, Josey JA. Efficient, stereoselective synthesis of oxazolo[3,2-a]pyrazin-5-ones: novel bicyclic lactam scaffolds from the bicyclocondensation of 3-aza-1,5-ketoacids and amino alcohols. Org Lett 2003; 5:2727-30. [PMID: 12868900 DOI: 10.1021/ol030065h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] The bicyclocondensation of 3-aza-1,5-ketoacids and amino alcohols furnished novel oxazolo[3,2-a]pyrazin-5-one scaffolds possessing angular, ring junction substituents in high yield with excellent levels of substrate-based diastereocontrol. Mild oxidation of serinol-derived scaffolds provided access to a new class of constrained dipeptide surrogates. Deprotection of the endocyclic amine contained within these scaffolds allows for further diversification via N-functionalization.
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Affiliation(s)
- Josef R Bencsik
- Array BioPharma, 3200 Walnut Street, Boulder, Colorado 80301, USA
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42
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Maison W, Adiwidjaja G. A short stereoselective synthesis of disubstituted cyclic amino acids. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)01267-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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43
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Marcantoni E, Mecozzi T, Petrini M. Allylation of exocyclic N-Acyliminium ions generated from chiral N-[1-(phenylsulfonyl)alkyl]oxazolidin-2-ones. J Org Chem 2002; 67:2989-94. [PMID: 11975557 DOI: 10.1021/jo0162888] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
N-[1-(Phenylsulfonyl)alkyl]oxazolidin-2-ones are successfully prepared by condensation of the corresponding optically active oxazolidin-2-ones with aldehydes and benzenesulfinic acid. At low temperature, in the presence of titanium tetrachloride, these sulfones are converted into N-acyliminium ions, which react with allyltrimethylsilane with a variable degree of stereoselectivity. The best results are obtained with (R)-5,5-dimethyl-4-phenyloxazolidin-2-one as a chiral auxiliary. Cleavage of the oxazolidin-2-one ring with lithium/ammonia affords the corresponding homoallylamines, which reveal an absolute configuration opposite that expected on the basis of the usual steric effects. A complexation of the Lewis acid with the N-acyliminium ion may be responsible of this rather unusual stereochemical outcome.
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Affiliation(s)
- Enrico Marcantoni
- Dipartimento di Scienze Chimiche, Università di Camerino, via S. Agostino 1, I-62032 Camerino, Italy
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44
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Sun H, Moeller KD. Silyl-substituted amino acids: new routes to the construction of selectively functionalized peptidomimetics. Org Lett 2002; 4:1547-50. [PMID: 11975625 DOI: 10.1021/ol025776e] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text]. Silylated amino acids have been incorporated into peptides and then converted into N-acyliminium ions with the use of an anodic oxidation reaction. The result is a method for selectively incorporating conformational constraints or external nucleophiles within the peptide.
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Affiliation(s)
- Haizhou Sun
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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45
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Khan NM, Cano M, Balasubramanian S. Synthesis of diastereomerically pure 1,4,5-substituted-2-oxopiperazines on solid-phase. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00268-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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46
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Laabs S, Münch W, Bats JW, Nubbemeyer U. Auxiliary controlled enantioselective synthesis of 3-aryl-prolines. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(01)01233-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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47
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Simpson JC, Ho C, Shands EFB, Gershengorn MC, Marshall GR, Moeller KD. Conformationally restricted TRH analogues: constraining the pyroglutamate region. Bioorg Med Chem 2002; 10:291-302. [PMID: 11741778 DOI: 10.1016/s0968-0896(01)00287-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A modified synthetic route has been developed so that the steric size of constraints added to the pyroglutamate region of TRH (pGluHisProNH(2)) can be varied. Both an analogue with a smaller ethylene bridge and a larger, more flexible propane bridge in this region have been synthesized. These analogues were synthesized in order to probe why the initial incorporation of an ethane bridge into this region of the molecule had led to an analogue with a binding constant and potency three times lower than that of an directly analogous unconstrained analogue. The data for both analogues indicated that the fall off in activity caused by the ethane bridge in the initial analogue was not caused by the size of the bridge.
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Affiliation(s)
- Jill C Simpson
- Department of Chemistry, Department of Molecular Biology and Pharmacology, Washington University, St. Louis, MO 63130, USA
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48
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Wells GJ, Tao M, Josef KA, Bihovsky R. 1,2-Benzothiazine 1,1-dioxide P(2)-P(3) peptide mimetic aldehyde calpain I inhibitors. J Med Chem 2001; 44:3488-503. [PMID: 11585453 DOI: 10.1021/jm010178b] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of peptide mimetic aldehyde inhibitors of calpain I was prepared in which the P(2) and P(3) amino acids were replaced by substituted 3,4-dihydro-1,2-benzothiazine-3-carboxylate 1,1-dioxides. The effect of 2, 6, and 7-benzothiazine substituents and the P(1) amino acid was examined. Potency of these inhibitors, 15c-p, against human recombinant calpain I is particularly dependent upon the 2-substituent, with methyl and ethyl generally more potent than hydrogen, isopropyl, isobutyl, or benzyl. The more potent diastereomer of 15m possesses the (S) absolute configuration at the 3-position of the 3,4-dihydro-1,2-benzothiazine. Potency of the best inhibitors in this series (IC(50) = 5-7 nM) compares favorably with that of conventional N-benzyloxycarbonyl dipeptide aldehyde inhibitors bearing L-Leu or L-Val residues at P(2). The achiral unsaturated 1,2-benzothiazine analogues 26a-d are also potent calpain I inhibitors, while 3,4-dihydro-2,1-benzoxathiin (15a,b), 1,2,4-benzothiadiazine (32a,b), and tetrahydroisoquinolinone (36a,b) analogues are less potent.
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Affiliation(s)
- G J Wells
- Department of Medicinal Chemistry, Cephalon, Inc., 145 Brandywine Parkway, West Chester, Pennsylvania 19380-4245, USA
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49
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Duan S, Moeller KD. Building constrained peptidomimetics: a convenient approach to 3-phenyl-5-vinyl substituted proline derivatives. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00532-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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50
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Alcaide B, Almendros P, Alonso JM, Aly MF. Rapid and stereocontrolled synthesis of racemic and optically pure highly functionalized pyrrolizidine systems via rearrangement of 1,3-dipolar cycloadducts derived from 2-azetidinone-tethered azomethine ylides. J Org Chem 2001; 66:1351-8. [PMID: 11312966 DOI: 10.1021/jo005686s] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work describes a convenient procedure for the straightforward preparation of polyfunctionalized enantiopure pyrrolizidine systems. The methodology capitalizes on a HCl(g)-promoted reaction of the 1,3-dipolar cycloadducts derived from 2-azetidinone-tethered azomethine ylides, smoothly affording different types of highly functionalized bi- and tricyclic systems in racemic and optically pure forms. This process involves a selective bond cleavage of the four-membered ring, followed by a rearrangement under the reaction conditions. The synthetic route employed was shown to be compatible with a variety of 4-oxoazetidine-2-carbaldehydes, alpha-amino esters, or dipolarophiles, offering a versatile entry to pyrrolizidine systems.
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Affiliation(s)
- B Alcaide
- Departamento de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
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