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Pierret A, Denhez C, Gros PC, Vasseur A. Zincate‐Mediated Remote Functionalisation of
p
‐Iodobenzyl Derivatives Through Metallotropy in 2‐Methyltetrahydrofuran as Key Solvent. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Clément Denhez
- Université de Reims Champagne Ardenne, CNRS, ICMR UMR 7312 51097 Reims France
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2
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Harenberg JH, Reddy Annapureddy R, Karaghiosoff K, Knochel P. Continuous Flow Preparation of Benzylic Sodium Organometallics. Angew Chem Int Ed Engl 2022; 61:e202203807. [PMID: 35416397 PMCID: PMC9400861 DOI: 10.1002/anie.202203807] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Indexed: 12/14/2022]
Abstract
We report a lateral sodiation of alkyl(hetero)arenes using on-demand generated hexane-soluble (2-ethylhexyl)sodium (1) in the presence of TMEDA. (2-Ethylhexyl)sodium (1) is prepared via a sodium packed-bed reactor and used for metalations at ambient temperature in batch as well as in continuous flow. The resulting benzylic sodium species are subsequently trapped with various electrophiles including carbonyl compounds, epoxides, oxetane, allyl/benzyl chlorides, alkyl halides and alkyl tosylates. Wurtz-type couplings with secondary alkyl halides and tosylates proceed under complete inversion of stereochemistry. Furthermore, the utility of this lateral sodiation is demonstrated in the synthesis of pharmaceutical relevant compounds. Thus, fingolimod is prepared from p-xylene applying the lateral sodiation twice. In addition, 7-fold isotopically labeled salmeterol-d7 and fenpiprane as well as precursors to super linear alkylbenzene (SLAB) surfactants are prepared.
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Affiliation(s)
- Johannes H. Harenberg
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstraße 5–13, Haus F81377MünchenGermany
| | | | - Konstantin Karaghiosoff
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstraße 5–13, Haus F81377MünchenGermany
| | - Paul Knochel
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstraße 5–13, Haus F81377MünchenGermany
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3
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Harenberg JH, Annapureddy RR, Karaghiosoff K, Knochel P. Continuous Flow Preparation of Benzylic Sodium Organometallics. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | | | - Paul Knochel
- Ludwig-Maximilians-Universitat Munchen Department of Chemistry Butenandtstr. 5-13 81377 München GERMANY
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4
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Ammonium Salts Catalyzed Acetalization Reactions in Green Ethereal Solvents. Catalysts 2020. [DOI: 10.3390/catal10101108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cyclopentyl methyl ether and 2-methyltetrahydrofuran, low impact ethereal solvents forming a positive azeotrope with water, were successfully employed as solvents in the synthesis of a variety of acetals carried out under Dean–Stark conditions in the presence of heterogeneous acidic catalysts. Under these conditions, ammonium salts, either as such or supported on SiO2, performed better or equally well than widely employed homogeneous and heterogeneous acidic catalysts such as p-toluenesulfonic acid, Amberlyst 15®, or Montmorillonite K10. Several examples highlight the advantage of tuning the relative acidities of ammonium salts by appropriately selecting the counterion. Within one of these examples, our protocol clearly outweighs the classic p-toluenesulfonic acid/toluene protocol in terms of chemoselectivity. Silica-supported catalysts were characterized by SEM, TEM, and FTIR spectroscopies, as well as by N2 physisorption. Such a characterization reveals an even distribution of ammonium salts on silica, thus confirming the formation of expected catalytic supports.
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Azzena U, Carraro M, Modugno G, Pisano L, Urtis L. Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents. Beilstein J Org Chem 2018; 14:1655-1659. [PMID: 30013691 PMCID: PMC6036977 DOI: 10.3762/bjoc.14.141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/19/2018] [Indexed: 11/23/2022] Open
Abstract
The application of heterogeneous catalysis and green solvents to the set up of widely employed reactions is a challenge in contemporary organic chemistry. We applied such an approach to the synthesis and further conversion of tetrahydropyranyl ethers, an important class of compounds widely employed in multistep syntheses. Several alcohols and phenols were almost quantitatively converted into the corresponding tetrahydropyranyl ethers in cyclopentyl methyl ether or 2-methyltetrahydrofuran employing NH4HSO4 supported on SiO2 as a recyclable acidic catalyst. Easy work up of the reaction mixtures and the versatility of the solvents allowed further conversion of the reaction products under one-pot reaction conditions.
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Affiliation(s)
- Ugo Azzena
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via Vienna 2, 07100 - Sassari, Italy
| | - Massimo Carraro
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via Vienna 2, 07100 - Sassari, Italy
| | - Gloria Modugno
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via Vienna 2, 07100 - Sassari, Italy
| | - Luisa Pisano
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via Vienna 2, 07100 - Sassari, Italy
| | - Luigi Urtis
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via Vienna 2, 07100 - Sassari, Italy
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Parris P, Duncan JN, Fleetwood A, Beierschmitt WP. Calculation of a permitted daily exposure value for the solvent 2-methyltetrahydrofuran. Regul Toxicol Pharmacol 2017; 87:54-63. [DOI: 10.1016/j.yrtph.2017.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 10/19/2022]
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Causero A, Elsen H, Ballmann G, Escalona A, Harder S. Calcium stilbene complexes: structures and dual reactivity. Chem Commun (Camb) 2017; 53:10386-10389. [PMID: 28876007 DOI: 10.1039/c7cc05792j] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Addition of a calcium hydride complex to diphenylacetylene gave a complex in which the stilbene dianion symmetrically bridges two Ca2+ions. With H2, this complex reacts as a double Brønsted base. In reaction with I2it provides two electrons.
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Affiliation(s)
- Andrea Causero
- Inorganic and Organometallic Chemistry
- University Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Holger Elsen
- Inorganic and Organometallic Chemistry
- University Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Gerd Ballmann
- Inorganic and Organometallic Chemistry
- University Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Ana Escalona
- Inorganic and Organometallic Chemistry
- University Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry
- University Erlangen-Nürnberg
- 91058 Erlangen
- Germany
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Azzena U. 1,2-Diaryl-1,2-disodioethanes: Versatile, Highly Reactive, and Tunable Synthetic Equivalents of Sodium Metal. Aust J Chem 2017. [DOI: 10.1071/ch16601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
1,2-Diaryl-1,2-disodioethanes are easily prepared, versatile, and stable diorganometals finding application in 1,2-reductive eliminations as well as in the degradation of several persistent organic pollutants as homogeneous synthetic equivalents of a highly reactive form of Na metal. Understanding their reactivity in terms of their different electron-donor power, which is strongly affected by the nature of substituents located either on the aromatic ring(s) or on the carbanionic centers, allowed rationalization of their employment not only as chemoselective single electron transfer reducing reagents, but also as bases in the generation of enediolates of arylacetic acids bearing easily reducible carbon–halogen bonds.
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Monticelli S, Castoldi L, Murgia I, Senatore R, Mazzeo E, Wackerlig J, Urban E, Langer T, Pace V. Recent advancements on the use of 2-methyltetrahydrofuran in organometallic chemistry. MONATSHEFTE FUR CHEMIE 2016; 148:37-48. [PMID: 28127090 PMCID: PMC5225237 DOI: 10.1007/s00706-016-1879-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 11/13/2016] [Indexed: 12/28/2022]
Abstract
ABSTRACT Since the introduction of 2-methyltetrahydrofuran as an useful alternative to the classical tetrahydrofuran, there has been a continuous interest in the synthetic community operating at academic and industrial towards it. In particular, the much higher stability that basic organometallic reagents display in 2-methyltetrahydrofuran makes it suitable for processes involving such sensitive species including asymmetric transformations. The easy formation of an azeotropic mixture with water, the substantial immiscibility with water, and the fact it derives from natural sources (corncobs or bagasse), allow to consider it in agreement with the Anastas' Geen Chemistry principles. In this minireview, selected examples of its employment in organometallic transformations ranging from carbanions to radical and transition metal-catalyzed processes are provided. GRAPHICAL ABSTRACT
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Affiliation(s)
- Serena Monticelli
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Laura Castoldi
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Irene Murgia
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Raffaele Senatore
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Eugenia Mazzeo
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Judith Wackerlig
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Ernst Urban
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Thierry Langer
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Vittorio Pace
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
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Azzena U, Carraro M, Pisano L, Mocci F, Antonello S, Maran F. Reducing properties of 1,2-dipyridyl-1,2-disodioethanes: chemical validation of theoretical and electrochemical predictions. RSC Adv 2016. [DOI: 10.1039/c6ra03303b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Theoretical calculations and electrochemical analysis were used to set up a relative scale for the reducing strength of the dianions of 1,2-dipyridylethenes, validated by studying their reactivity towards halogenated benzoic and arylacetic acids.
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Affiliation(s)
- U. Azzena
- Dipartimento di Chimica e Farmacia
- Università di Sassari
- I-07100 Sassari
- Italy
| | - M. Carraro
- Dipartimento di Chimica e Farmacia
- Università di Sassari
- I-07100 Sassari
- Italy
| | - L. Pisano
- Dipartimento di Chimica e Farmacia
- Università di Sassari
- I-07100 Sassari
- Italy
| | - F. Mocci
- Dipartimento di Scienze Chimiche e Geologiche
- Università di Cagliari
- Complesso Universitario
- I – 09042 Monserrato (Ca)
- Italy
| | - S. Antonello
- Dipartimento di Scienze Chimiche e Geologiche
- Università di Padova
- I-35131 Padova
- Italy
| | - F. Maran
- Dipartimento di Scienze Chimiche e Geologiche
- Università di Padova
- I-35131 Padova
- Italy
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Azzena U, Carraro M, Meloni C, Murgia I, Pisano L, Pittalis M, Luisi R, Musio B, Degennaro L. Regio- and stereochemistry of Na-mediated reductive cleavage of alkyl aryl ethers. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.tetasy.2014.10.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Pace V, Hoyos P, Alcántara AR, Holzer W. Chemoselective CaO-mediated acylation of alcohols and amines in 2-methyltetrahydrofuran. CHEMSUSCHEM 2013; 6:905-910. [PMID: 23532956 DOI: 10.1002/cssc.201200922] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Indexed: 06/02/2023]
Abstract
Calcium oxide is proposed as an innocuous acid scavenger for the chemoselective synthesis of amide- and ester-type compounds. Although these molecules have wide spread applications in organic and pharmaceutical chemistry, and a large number of routes have been designed for their synthesis, the development of more efficient and environmentally friendly acylation strategies remains an ongoing challenge. The use of CaO allows for the stoichiometric acylation of primary alcohols in the presence of phenols or tertiary alcohols; amines can also be subjected to acylation reactions in the presence of hydroxyl groups. Chirality is obtained through acylation if the starting material is an optically pure alcohol or if a chiral acylating agent is used. Furthermore, the use of 2-methyltetrahydrofuran (2-MeTHF), a more ecofriendly solvent, leads to maximized yields. This protocol is successfully applied to the synthesis of an interesting N-aryloxazolidin-2-one intermediate for the preparation of linezolid-type compounds.
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Affiliation(s)
- Vittorio Pace
- Department of Drug and Natural Product Synthesis, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
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Active-alkali metal promoted reductive desulfurization of dibenzothiophene and its hindered analogues. Tetrahedron 2013. [DOI: 10.1016/j.tet.2012.10.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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