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Rao CN, Reissig HU. Samarium(II)‐Promoted Cyclizations of Non‐activated Indolyl Sulfinyl Imines to Polycyclic Tertiary Carbinamines. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Chintada Nageswara Rao
- Freie Universität Berlin: Freie Universitat Berlin Institut für Chemie und Biochemie 14195 Berlin GERMANY
| | - Hans-Ulrich Reissig
- Freie Universität Berlin Institut für Chemie und Biochemie Takustr. 3 14195 Berlin GERMANY
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2
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Rao CN, Reissig H. Synthesis and Evaluation of Enantiopure HMPA Analogs in Samarium‐Diiodide‐Promoted Dearomatizations of N‐Acylated Indole Derivatives. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101065] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Chintada Nageswara Rao
- Institut für Chemie und Biochemie Freie Universität Berlin Takustrasse 3 14195 Berlin Germany
| | - Hans‐Ulrich Reissig
- Institut für Chemie und Biochemie Freie Universität Berlin Takustrasse 3 14195 Berlin Germany
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Lockley WJS, Venanzi NAE, Crane GJ. Studies of hydrogen isotope scrambling during the dehalogenation of aromatic chloro-compounds with deuterium gas over palladium catalysts. J Labelled Comp Radiopharm 2020; 63:531-552. [PMID: 32886808 DOI: 10.1002/jlcr.3878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/23/2020] [Accepted: 08/19/2020] [Indexed: 11/06/2022]
Abstract
Catalytic dehalogenation of aromatic halides using isotopic hydrogen gas is an important strategy for labelling pharmaceuticals, biochemicals, environmental agents and so forth. To extend, improve and further understand this process, studies have been carried out on the scrambling of deuterium isotope with protium during the catalytic deuterodehalogenation of model aryl chlorides using deuterium gas and a palladium on carbon catalyst in tetrahydrofuran solution. The degree of scrambling was greatest with electron-rich chloroarene rings. The tetrahydrofuran solvent and the triethylamine base were not the source of the undesired protium; instead, it arose, substantially, from the water content of the catalyst, though other sources of protium may also be present on the catalyst. Replacement of the Pd/C catalyst with one prepared in situ by reduction of palladium trifluoroacetate with deuterium gas and dispersed upon micronised polytetrafluoroethylene led to much reduced scrambling (typically 0-6% compared with up to 40% for palladium on carbon) and to high atom% abundance, regiospecific labelling. The improved catalytic system now enables efficient polydeuteration via the dehalogenation of polyhalogenated precursors, making the procedure viable for the preparation of MS internal standards and, potentially, for high specific activity tritium labelling.
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Affiliation(s)
- William J S Lockley
- Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, UK
| | | | - Georgie J Crane
- Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, UK
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McDonald CE, Bendorf HD, Mauck JR, McAtee CC, Green AI, Ciccarelli DJ, Bendyk CA, Conrad BJ, Delgado AT. The SmI 2/TEU --Mediated Cyclization of Unsaturated Halides. Org Lett 2020; 22:5685-5689. [PMID: 32603130 DOI: 10.1021/acs.orglett.0c02074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The combination of SmI2 and the conjugate base of triethylurea (TEU-) has been shown to favor the cyclization of unsaturated halides over direct reduction to a much greater extent than other SmI2-based reductants. Aryl, heteroaryl, and alkyl halides (X = Br, Cl, F) readily undergo heterocyclization and carbocyclization in the presence of SmI2/TEU-.
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Affiliation(s)
- Chriss E McDonald
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
| | - Holly D Bendorf
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
| | - Joseph R Mauck
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
| | - Christopher C McAtee
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
| | - Ahren I Green
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
| | - David J Ciccarelli
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
| | - Cassandra A Bendyk
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
| | - Brandon J Conrad
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
| | - Angelique T Delgado
- Department of Chemistry, Lycoming College, One College Place, Williamsport, Pennsylvania 17701, United States
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Beemelmanns C, Nitsch D, Bentz C, Reissig HU. Stereoselective Cascade Cyclizations with Samarium Diiodide to Tetracyclic Indolines: Precursors of Fluorostrychnines and Brucine. Chemistry 2019; 25:8780-8789. [PMID: 31033048 DOI: 10.1002/chem.201900087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/25/2019] [Indexed: 12/16/2022]
Abstract
A series of γ-indolylketones with fluorine, cyano or alkoxy substituents at the benzene moiety was prepared and subjected to samarium diiodide-promoted cyclization reactions. The desired dearomatizing ketyl cascade reaction forming two new rings proceeded in all cases with high diastereoselectivity, but with differing product distribution. In most cases, the desired annulated tetracyclic compounds were obtained in moderate to good yields, but as second product tetracyclic spirolactones were isolated in up to 29 % yield. The reaction rate was influenced by the substituents at the benzene moiety of the substrate as expected, with electron-accepting groups accelerating and electron-donating groups decelerating the cyclization process. In case of a difluoro-substituted γ-indolylketone a partial defluorination was observed. The intermediate samarium enolate of the tetracyclic products could be trapped by adding reactive alkylating agents as electrophiles delivering products with quarternary carbons. In the case of a dimethoxy-substituted tetracyclic cyclization product a subsequent reductive amination stereoselectively provided a pentacyclic compound that was subsequently N-protected and subjected to a regioselective elimination. The obtained functionalized pentacyclic product should be convertible into the alkaloid brucine by four well-established steps. Overall, the presented report shows that functionalized tetracyclic compounds with different substituents are rapidly available with the samarium diiodide cascade cyclization as crucial step. Hence, analogues of the landmark alkaloid strychnine, for example, with specific fluorine substitutions, should be easily accessible.
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Affiliation(s)
- Christine Beemelmanns
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany.,Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie, Beutenbergstraße 11a, 07745, Jena, Germany
| | - Dominik Nitsch
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany
| | - Christoph Bentz
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany
| | - Hans-Ulrich Reissig
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany
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Recent Advances in the Catalytic Synthesis of Imidazolidin-2-ones and Benzimidazolidin-2-ones. Catalysts 2019. [DOI: 10.3390/catal9010028] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
2-Imidazolidinone and its analogues are omnipresent structural motifs of pharmaceuticals, natural products, chiral auxiliaries, and intermediates in organic syntheses. Over the years, continuous efforts have been addressed to the development of sustainable and more efficient protocols for the synthesis of these heterocycles. This review gives a summary of the catalytic strategies to access imidazolidin-2-ones and benzimidazolidin-2-ones that have appeared in the literature from 2010 to 2018. Particularly important contributions beyond the timespan will be mentioned. The review is organized in four main chapters that identify the most common approaches to imidazolidin-2-one derivatives: (1) the direct incorporation of the carbonyl group into 1,2-diamines, (2) the diamination of olefins, (3) the intramolecular hydroamination of linear urea derivatives and (4) aziridine ring expansion. Methods not included in this classification will be addressed in the miscellaneous section.
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Kanega R, Onishi N, Szalda DJ, Ertem MZ, Muckerman JT, Fujita E, Himeda Y. CO2 Hydrogenation Catalysts with Deprotonated Picolinamide Ligands. ACS Catal 2017. [DOI: 10.1021/acscatal.7b02280] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryoichi Kanega
- Research Institute of Energy Frontier, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Naoya Onishi
- Research Institute of Energy Frontier, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - David J. Szalda
- Department of Natural Science, Baruch College, CUNY, New York, New York 10010-5585, United States
| | - Mehmed Z. Ertem
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - James T. Muckerman
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Etsuko Fujita
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Yuichiro Himeda
- Research Institute of Energy Frontier, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
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