1
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Pal K, Volla CMR. Catalytic Insertion Reactions of α-Imino Carbenoids. CHEM REC 2021; 21:4032-4058. [PMID: 34791794 DOI: 10.1002/tcr.202100238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 12/31/2022]
Abstract
Over the past decade, α-imino carbenoids generated via transition metal (such as rhodium, nickel, copper, palladium, silver) catalyzed denitrogenative ring-opening of N-sulfonyl-1,2,3-triazoles have found an extensive account of applications in synthetic organic chemistry. Particularly, they have been widely utilized as a donor/acceptor carbene complex in a range of transformations leading to diverse nitrogen containing compounds and heterocycles. Along the same direction, 3-diazoindolin-2-imines were successfully applied as an alternative source of α-imino carbenoid precursors for the development of a number of methodologies to access diverse indole derivatives. This review summarizes the insertion reactions of α-imino metal carbenes derived from N-sulfonyl-1,2,3-triazoles and 3-diazoindolin-2-imines.
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Affiliation(s)
- Kuntal Pal
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Chandra M R Volla
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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2
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Fath V, Lau P, Greve C, Weller P, Kockmann N, Röder T. Simultaneous self-optimisation of yield and purity through successive combination of inline FT-IR spectroscopy and online mass spectrometry in flow reactions. J Flow Chem 2021. [DOI: 10.1007/s41981-021-00140-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AbstractSelf-optimisation constitutes a very helpful tool for chemical process development, both in lab and in industrial applications. However, research on the application of model-free autonomous optimisation strategies (based on experimental investigation) for complex reactions of high industrial significance, which involve considerable intermediate and by-product formation, is still in an early stage. This article describes the development of an enhanced autonomous microfluidic reactor platform for organolithium and epoxide reactions that incorporates a successive combination of inline FT-IR spectrometer and online mass spectrometer. Experimental data is collected in real-time and used as feedback for the optimisation algorithms (modified Simplex algorithm and Design of Experiments) without time delay. An efficient approach to handle intricate optimisation problems is presented, where the inline FT-IR measurements are used to monitor the reaction’s main components, whereas the mass spectrometer’s high sensitivity permits insights into the formation of by-products. To demonstrate the platform’s flexibility, optimal reaction conditions of two organic syntheses are identified. Both pose several challenges, as complex reaction mechanisms are involved, leading to a large number of variable parameters, and a considerable amount of by-products is generated under non-ideal process conditions. Through multidimensional real-time optimisation, the platform supersedes labor- and cost-intensive work-up procedures, while diminishing waste generation, too. Thus, it renders production processes more efficient and contributes to their overall sustainability.
Graphical abstract
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3
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Pseudo-Dipeptide Bearing α,α-Difluoromethyl Ketone Moiety as Electrophilic Warhead with Activity against Coronaviruses. Int J Mol Sci 2021; 22:ijms22031398. [PMID: 33573283 PMCID: PMC7866854 DOI: 10.3390/ijms22031398] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 01/26/2021] [Indexed: 12/18/2022] Open
Abstract
The synthesis of α-fluorinated methyl ketones has always been challenging. New methods based on the homologation chemistry via nucleophilic halocarbenoid transfer, carried out recently in our labs, allowed us to design and synthesize a target-directed dipeptidyl α,α-difluoromethyl ketone (DFMK) 8 as a potential antiviral agent with activity against human coronaviruses. The ability of the newly synthesized compound to inhibit viral replication was evaluated by a viral cytopathic effect (CPE)-based assay performed on MCR5 cells infected with one of the four human coronaviruses associated with respiratory distress, i.e., hCoV-229E, showing antiproliferative activity in the micromolar range (EC50 = 12.9 ± 1.22 µM), with a very low cytotoxicity profile (CC50 = 170 ± 3.79 µM, 307 ± 11.63 µM, and 174 ± 7.6 µM for A549, human embryonic lung fibroblasts (HELFs), and MRC5 cells, respectively). Docking and molecular dynamics simulations studies indicated that 8 efficaciously binds to the intended target hCoV-229E main protease (Mpro). Moreover, due to the high similarity between hCoV-229E Mpro and SARS-CoV-2 Mpro, we also performed the in silico analysis towards the second target, which showed results comparable to those obtained for hCoV-229E Mpro and promising in terms of energy of binding and docking pose.
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4
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Ielo L, Pillari V, Miele M, Holzer W, Pace V. Consecutive C1‐Homologation / Displacement Strategy for Converting Thiosulfonates into
O,S‐
Oxothioacetals. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000919] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Laura Ielo
- University of Vienna Department of Pharmaceutical Chemistry Althanstrasse 14 1090 Vienna Austria
| | - Veronica Pillari
- University of Vienna Department of Pharmaceutical Chemistry Althanstrasse 14 1090 Vienna Austria
| | - Margherita Miele
- University of Vienna Department of Pharmaceutical Chemistry Althanstrasse 14 1090 Vienna Austria
| | - Wolfgang Holzer
- University of Vienna Department of Pharmaceutical Chemistry Althanstrasse 14 1090 Vienna Austria
| | - Vittorio Pace
- University of Vienna Department of Pharmaceutical Chemistry Althanstrasse 14 1090 Vienna Austria
- University of Turin Department of Chemistry Via P. Giuria 7 10125 Turin Italy
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5
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Ielo L, Pace V, Pillari V, Miele M, Castiglione D. Carbenoid-Mediated Homologation Tactics for Assembling (Fluorinated) Epoxides and Aziridines. Synlett 2020. [DOI: 10.1055/s-0040-1706404] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Homologation strategies provide highly versatile tools in organic synthesis for the introduction of a CH2 group into a given carbon skeleton. The operation can result in diverse structural motifs by tuning of the reaction conditions and the nature of the homologating agent. In this Account, concisely contextualizing our work with lithium carbenoids (LiCH2X, LiCHXY etc) for homologating carbon-centered electrophiles, we focus on the assembly of three-membered cycles featuring fluorinated substituents. Two illustrative case studies are considered: (1) the development and employment of fluorinated carbenoids en route to rare α-fluoroepoxides and aziridines, and (2) the installation of up to halomethylenic groups on trifluoroimidoylacetyl chlorides (TFAICs) for preparing CF3-containing halo- and halomethylaziridines. Collectively, we demonstrate that the initial homologation event generated by the installation of the carbenoid, upon modulation of the conditions, serves as a tool for creating fluorinated building blocks in a single operation.
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Affiliation(s)
- Laura Ielo
- University of Vienna, Department of Pharmaceutical Chemistry
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6
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von Keutz T, Cantillo D, Kappe CO. Continuous Flow Synthesis of Terminal Epoxides from Ketones Using in Situ Generated Bromomethyl Lithium. Org Lett 2019; 21:10094-10098. [PMID: 31794232 DOI: 10.1021/acs.orglett.9b04072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A scalable procedure for the direct preparation of epoxides from ketones has been developed. The method is based on the carefully controlled generation of (bromomethyl)lithium (LiCH2Br) from inexpensive CH2Br2 and MeLi in a continuous flow reactor. The reaction has shown excellent selectivity for a variety of substrates, including α-chloroketones, which typically fail under classic Corey-Chaykovsky conditions. This advantage has been used to develop a novel route toward the drug fluconazole.
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Affiliation(s)
- Timo von Keutz
- Institute of Chemistry , University of Graz , NAWI Graz, Heinrichstrasse 28 , 8010 Graz , Austria.,Center for Continuous Flow Synthesis and Processing (CCFLOW) , Research Center Pharmaceutical Engineering GmbH (RCPE) , Inffeldgasse 13 , 8010 Graz , Austria
| | - David Cantillo
- Institute of Chemistry , University of Graz , NAWI Graz, Heinrichstrasse 28 , 8010 Graz , Austria.,Center for Continuous Flow Synthesis and Processing (CCFLOW) , Research Center Pharmaceutical Engineering GmbH (RCPE) , Inffeldgasse 13 , 8010 Graz , Austria
| | - C Oliver Kappe
- Institute of Chemistry , University of Graz , NAWI Graz, Heinrichstrasse 28 , 8010 Graz , Austria.,Center for Continuous Flow Synthesis and Processing (CCFLOW) , Research Center Pharmaceutical Engineering GmbH (RCPE) , Inffeldgasse 13 , 8010 Graz , Austria
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7
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Monticelli S, Holzer W, Langer T, Roller A, Olofsson B, Pace V. Sustainable Asymmetric Organolithium Chemistry: Enantio- and Chemoselective Acylations through Recycling of Solvent, Sparteine, and Weinreb "Amine". CHEMSUSCHEM 2019; 12:1147-1154. [PMID: 30614208 PMCID: PMC6704367 DOI: 10.1002/cssc.201802815] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 12/20/2018] [Indexed: 05/10/2023]
Abstract
The well-established Hoppe-Beak chemistry, which involves enantioselective generation of organolithium compounds in the presence of (-)-sparteine, was revisited and applied to unprecedented acylations with Weinreb amides to access highly enantioenriched α-oxyketones and cyclic α-aminoketones. Recycling of the sustainable solvent cyclopentyl methyl ether, sparteine, and the released Weinreb "amine" [HNMe(OMe)] was possible through a simple work-up procedure that enabled full recovery of these precious materials. The methodology features a robust scope and flexibility, thus allowing the enantioselective preparation of scaffolds amenable of further derivatization.
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Affiliation(s)
- Serena Monticelli
- Department of Pharmaceutical ChemistryUniversity of ViennaAlthanstrasse,14Vienna1090Austria
| | - Wolfgang Holzer
- Department of Pharmaceutical ChemistryUniversity of ViennaAlthanstrasse,14Vienna1090Austria
| | - Thierry Langer
- Department of Pharmaceutical ChemistryUniversity of ViennaAlthanstrasse,14Vienna1090Austria
| | - Alexander Roller
- X-Ray Structure Analysis CenterUniversity of ViennaWaehringerstrasse 42Vienna1090Austria
| | - Berit Olofsson
- Department of Organic Chemistry, Arrhenius LaboratoryStockholm UniversitySe-106 91StockholmSweden
| | - Vittorio Pace
- Department of Pharmaceutical ChemistryUniversity of ViennaAlthanstrasse,14Vienna1090Austria
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8
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Monticelli S, Urban E, Langer T, Holzer W, Pace V. A Straightforward Homologation of Carbon Dioxide with Magnesium Carbenoids en Route to α-Halocarboxylic Acids. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201801614] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Serena Monticelli
- University of Vienna; Department of Pharmaceutical Chemistry; Althanstrasse 14-1090 Vienna Austria
| | - Ernst Urban
- University of Vienna; Department of Pharmaceutical Chemistry; Althanstrasse 14-1090 Vienna Austria
| | - Thierry Langer
- University of Vienna; Department of Pharmaceutical Chemistry; Althanstrasse 14-1090 Vienna Austria
| | - Wolfgang Holzer
- University of Vienna; Department of Pharmaceutical Chemistry; Althanstrasse 14-1090 Vienna Austria
| | - Vittorio Pace
- University of Vienna; Department of Pharmaceutical Chemistry; Althanstrasse 14-1090 Vienna Austria
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9
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Castoldi L, Monticelli S, Senatore R, Ielo L, Pace V. Homologation chemistry with nucleophilic α-substituted organometallic reagents: chemocontrol, new concepts and (solved) challenges. Chem Commun (Camb) 2018; 54:6692-6704. [PMID: 29850663 DOI: 10.1039/c8cc02499e] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The transfer of a reactive nucleophilic CH2X unit into a preformed bond enables the introduction of a fragment featuring the exact and desired degree of functionalization through a single synthetic operation. The instability of metallated α-organometallic species often poses serious questions regarding the practicability of using this conceptually intuitive and simple approach for forming C-C or C-heteroatom bonds. A deep understanding of processes regulating the formation of these nucleophiles is a precious source of inspiration not only for successfully applying theoretically feasible transformations (i.e. determining how to employ a given reagent), but also for designing new reactions which ultimately lead to the introduction of molecular complexity via short experimental sequences.
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Affiliation(s)
- Laura Castoldi
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
| | - Serena Monticelli
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
| | - Raffaele Senatore
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
| | - Laura Ielo
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
| | - Vittorio Pace
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
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10
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Monticelli S, Rui M, Castoldi L, Missere G, Pace V. A practical guide for using lithium halocarbenoids in homologation reactions. MONATSHEFTE FUR CHEMIE 2018; 149:1285-1291. [PMID: 29983454 PMCID: PMC6006224 DOI: 10.1007/s00706-018-2232-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 05/13/2018] [Indexed: 12/24/2022]
Abstract
ABSTRACT Lithium halocarbenoids are versatile reagents for accomplishing homologation processes. The fast α-elimination they suffer has been considered an important limitation for their extensive use. Herein, we present a series of practical considerations for an effective employment in the homologation of selected carbon electrophiles. GRAPHICAL ABSTRACT
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Affiliation(s)
- Serena Monticelli
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Marta Rui
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Laura Castoldi
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Giada Missere
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Vittorio Pace
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
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11
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Merging lithium carbenoid homologation and enzymatic reduction: A combinative approach to the HIV-protease inhibitor Nelfinavir. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.03.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Senatore R, Ielo L, Urban E, Holzer W, Pace V. Substituted α-Sulfur Methyl Carbanions: Effective Homologating Agents for the Chemoselective Preparation of β-Oxo Thioethers from Weinreb Amides. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800095] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Raffaele Senatore
- Department of Pharmaceutical Chemistry; University of Vienna; Althanstrasse 14 - 1090 Vienna Austria
| | - Laura Ielo
- Department of Pharmaceutical Chemistry; University of Vienna; Althanstrasse 14 - 1090 Vienna Austria
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences; University of Messina; Viale Annunziata 98168 Messina Italy
| | - Ernst Urban
- Department of Pharmaceutical Chemistry; University of Vienna; Althanstrasse 14 - 1090 Vienna Austria
| | - Wolfgang Holzer
- Department of Pharmaceutical Chemistry; University of Vienna; Althanstrasse 14 - 1090 Vienna Austria
| | - Vittorio Pace
- Department of Pharmaceutical Chemistry; University of Vienna; Althanstrasse 14 - 1090 Vienna Austria
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13
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Pace V, Monticelli S, de la Vega-Hernández K, Castoldi L. Isocyanates and isothiocyanates as versatile platforms for accessing (thio)amide-type compounds. Org Biomol Chem 2018; 14:7848-54. [PMID: 27461156 DOI: 10.1039/c6ob00766j] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The addition of carbon (Grignard and organolithium reagents) and hydride nucleophiles (Schwartz reagent) to isocyanates and isothiocyanates constitutes a versatile, direct and high yielding approach to the synthesis of functionalized (thio)amide derivatives including haloamides and formamides. The chemoselective delivery of a nucleophilic (eventually configurationally stable) organometallic species to a given iso(thio)cyanate is the crucial parameter for the success of the strategy. Thus, the influence of the factors governing classical methodologies (e.g. dehydrative condensation) such as steric hindrance and electronic properties of the reactants become practically negligible.
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Affiliation(s)
- Vittorio Pace
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
| | - Serena Monticelli
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
| | - Karen de la Vega-Hernández
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
| | - Laura Castoldi
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse, 14, A-1090, Vienna, Austria.
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14
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Parisi G, Colella M, Monticelli S, Romanazzi G, Holzer W, Langer T, Degennaro L, Pace V, Luisi R. Exploiting a "Beast" in Carbenoid Chemistry: Development of a Straightforward Direct Nucleophilic Fluoromethylation Strategy. J Am Chem Soc 2017; 139:13648-13651. [PMID: 28892363 DOI: 10.1021/jacs.7b07891] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The first direct and straightforward nucleophilic fluoromethylation of organic compounds is reported. The tactic employs a "fleeting" lithium fluorocarbenoid (LiCH2F) generated from commercially available fluoroiodomethane. Precise reaction conditions were developed for the generation and synthetic exploitation of such a labile species. The versatility of the strategy is showcased in ca. 50 examples involving a plethora of electrophiles. Highly valuable chemicals such as fluoroalcohols, fluoroamines, and fluoromethylated oxygenated heterocycles could be prepared in very good yields through a single synthetic operation. The scalability of the reaction and its application to complex molecular architectures (e.g., steroids) are documented.
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Affiliation(s)
- Giovanna Parisi
- Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" , Via E. Orabona 4, 70125 Bari, Italy.,Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse 14, 1090 Vienna, Austria
| | - Marco Colella
- Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" , Via E. Orabona 4, 70125 Bari, Italy
| | - Serena Monticelli
- Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse 14, 1090 Vienna, Austria
| | | | - Wolfgang Holzer
- Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse 14, 1090 Vienna, Austria
| | - Thierry Langer
- Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse 14, 1090 Vienna, Austria
| | - Leonardo Degennaro
- Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" , Via E. Orabona 4, 70125 Bari, Italy
| | - Vittorio Pace
- Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse 14, 1090 Vienna, Austria
| | - Renzo Luisi
- Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" , Via E. Orabona 4, 70125 Bari, Italy
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15
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Pace V, Castoldi L, Mazzeo E, Rui M, Langer T, Holzer W. Efficient Access to All‐Carbon Quaternary and Tertiary α‐Functionalized Homoallyl‐type Aldehydes from Ketones. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201706236] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Vittorio Pace
- Department of Pharmaceutical Chemistry University of Vienna Althanstrasse, 14 1090 Vienna Austria
| | - Laura Castoldi
- Department of Pharmaceutical Chemistry University of Vienna Althanstrasse, 14 1090 Vienna Austria
| | - Eugenia Mazzeo
- Department of Pharmaceutical Chemistry University of Vienna Althanstrasse, 14 1090 Vienna Austria
| | - Marta Rui
- Department of Pharmaceutical Chemistry University of Vienna Althanstrasse, 14 1090 Vienna Austria
| | - Thierry Langer
- Department of Pharmaceutical Chemistry University of Vienna Althanstrasse, 14 1090 Vienna Austria
| | - Wolfgang Holzer
- Department of Pharmaceutical Chemistry University of Vienna Althanstrasse, 14 1090 Vienna Austria
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16
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Pace V, Castoldi L, Mazzeo E, Rui M, Langer T, Holzer W. Efficient Access to All-Carbon Quaternary and Tertiary α-Functionalized Homoallyl-type Aldehydes from Ketones. Angew Chem Int Ed Engl 2017; 56:12677-12682. [PMID: 28722252 DOI: 10.1002/anie.201706236] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Indexed: 12/30/2022]
Abstract
β,γ-Unsaturated aldehydes with all-carbon quaternary or tertiary α-centers were rapidly assembled from ketones through a unique synthetic operation consisting of 1) C1 homologation, 2) Lewis acid mediated epoxide-aldehyde isomerization, and 3) electrophilic trapping. The synthetic equivalence of a vinyl oxirane and a β,γ-unsaturated aldehyde is the key concept of this previously undisclosed tactic. Mechanistic studies and labeling experiments suggest that an aldehyde enolate is a crucial intermediate. The homologating carbenoid formation plays a critical role in determining the chemoselectivity.
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Affiliation(s)
- Vittorio Pace
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse, 14, 1090, Vienna, Austria
| | - Laura Castoldi
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse, 14, 1090, Vienna, Austria
| | - Eugenia Mazzeo
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse, 14, 1090, Vienna, Austria
| | - Marta Rui
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse, 14, 1090, Vienna, Austria
| | - Thierry Langer
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse, 14, 1090, Vienna, Austria
| | - Wolfgang Holzer
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse, 14, 1090, Vienna, Austria
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17
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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: 60] [Impact Index Per Article: 7.5] [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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18
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Gessner VH. Stability and reactivity control of carbenoids: recent advances and perspectives. Chem Commun (Camb) 2016; 52:12011-12023. [PMID: 27498609 DOI: 10.1039/c6cc05524a] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Metal carbenoids such as lithium or Simmons-Smith-type reagents are widely used in organic synthesis, particularly in cyclopropanation and homologation reactions. These reagents are often highly reactive and thermally labile, thus limiting their isolation and hampering the development of new synthetic applications. Recent years however, have shown that by means of systematic stabilization a control of reactivity and the development of new applications is possible. This feature article documents recent developments in the control of carbenoid reactivity and stability and highlights structural and electronic properties as well as applications in main group element and transition metal chemistry.
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Affiliation(s)
- Viktoria H Gessner
- Inorganic Chemistry II - Organometallic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum, Germany.
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19
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Pace V, Holzer W, De Kimpe N. Lithium Halomethylcarbenoids: Preparation and Use in the Homologation of Carbon Electrophiles. CHEM REC 2016; 16:2061-76. [PMID: 27381551 DOI: 10.1002/tcr.201600011] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Indexed: 11/06/2022]
Abstract
α-Halomethyllithium carbenoids are useful homologating reagents which - reacting under proper reaction conditions as carbanions - enable the installation via nucleophilic addition of a reactive halomethyl fragment onto a preformed carbon-heteroatom bond. The pronounced thermolability represented - since seminal studies by Köbrich - the Achilles' heel of these reagents: the use of Barbier-type methodologies (i.e., the electrophile should be present in the reaction mixture prior to the formation of the carbenoid) was pivotal in order to suppress decomposition through α-elimination processes. Nowadays, the use of low temperatures (-78 °C) guarantees reliable procedures and, significantly, the employment of microreactor technologies allows external trapping to be performed even at higher temperatures as reported by Luisi. We will discuss the α-halomethyllithium-mediated homologations of a series of carbon electrophiles such as carbonyl compounds, imines, esters, Weinreb amides, and isocyanates.
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Affiliation(s)
- Vittorio Pace
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Wolfgang Holzer
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Norbert De Kimpe
- Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
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Parisi G, Zenzola M, Capitanelli E, Carlucci C, Romanazzi G, Pisano L, Degennaro L, Luisi R. Exploiting structural and conformational effects for a site-selective lithiation of azetidines. PURE APPL CHEM 2016. [DOI: 10.1515/pac-2016-0602] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
AbstractInterest in molecular structures bearing four-membered heterocycles (FMHs) is growing due to the possibility to explore new regions of the chemical space and get new lead molecules. Our interest in the development of divergent synthesis of functionalized FMHs, prompted us to disclose factors affecting the reactivity of nitrogen-bearing FMHs towards metalating agents. Our investigations demonstrated that structural factors and conformational preferences need to be considered in planning a site-selective functionalization of azetidines. It will be showed how such factors could have pivotal importance in the reactivity of FMHs.
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Affiliation(s)
- Giovanna Parisi
- 1Department of Pharmacy – Drug Sciences, University of Bari “A. Moro” Via E. Orabona 4, 70125 – Italy
| | - Marina Zenzola
- 1Department of Pharmacy – Drug Sciences, University of Bari “A. Moro” Via E. Orabona 4, 70125 – Italy
| | - Emanuela Capitanelli
- 1Department of Pharmacy – Drug Sciences, University of Bari “A. Moro” Via E. Orabona 4, 70125 – Italy
| | - Claudia Carlucci
- 1Department of Pharmacy – Drug Sciences, University of Bari “A. Moro” Via E. Orabona 4, 70125 – Italy
| | - Giuseppe Romanazzi
- 2DICATECh, Politecnico di Bari, Via E. Orabona 4, 70125 – Italy
- 3CNR NANOTEC−Istituto di Nanotecnologia, Polo di Nanotecnologia c/o Campus Ecotekne, via Monteroni, 73100 Lecce, Italy
| | - Luisa Pisano
- 4Department of Chemistry and Pharmacy, University of Sassari, Via Vienna 2, 07100 – Italy
| | - Leonardo Degennaro
- 1Department of Pharmacy – Drug Sciences, University of Bari “A. Moro” Via E. Orabona 4, 70125 – Italy
| | - Renzo Luisi
- 1Department of Pharmacy – Drug Sciences, University of Bari “A. Moro” Via E. Orabona 4, 70125 – Italy
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Pace V, Murgia I, Westermayer S, Langer T, Holzer W. Highly efficient synthesis of functionalized α-oxyketones via Weinreb amides homologation with α-oxygenated organolithiums. Chem Commun (Camb) 2016; 52:7584-7. [PMID: 27220327 DOI: 10.1039/c6cc03532a] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient, chemoselective homologation of Weinreb amides to the corresponding variously substituted α-oxyketones has been developed via the addition of lithiated α-oxygenated species. This one-step, experimentally easy, high yielding protocol is amenable not only for accessing simple α-oxyketones but also for more complex substituted ones ranging from primary and secondary alkyl-type to aromatic ones. Full delivery of the stereochemical information contained in the starting materials is observed through both the employment of enantioenriched Weinreb amides and optically active organolithium species.
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Affiliation(s)
- Vittorio Pace
- University of Vienna - Department of Pharmaceutical Chemistry, Althanstrasse, 14. A-1090, Vienna, Austria.
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Pace V, de la Vega-Hernández K, Urban E, Langer T. Chemoselective Schwartz Reagent Mediated Reduction of Isocyanates to Formamides. Org Lett 2016; 18:2750-3. [PMID: 27218199 DOI: 10.1021/acs.orglett.6b01226] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Addition of the in situ generated Schwartz reagent to widely available isocyanates constitutes a chemoselective, high-yielding, and versatile approach to the synthesis of variously functionalized formamides. Steric and electronic factors or the presence of sensitive functionalities (esters, nitro groups, nitriles, alkenes) do not compromise the potential of the method. Full preservation of the stereochemical information contained in the starting materials is observed. The use of formamides in the nucleophilic addition of organometallic reagents (Chida-Sato allylation, Charette-Huang addition to imidoyl triflate activated amides, Matteson homologation of boronic esters) is briefly investigated.
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Affiliation(s)
- Vittorio Pace
- Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse, 14, A-1090 Vienna, Austria
| | - Karen de la Vega-Hernández
- Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse, 14, A-1090 Vienna, Austria.,Institute of Pharmacy and Food Sciences, University of Havana , 23rd Street, 21425-13600 Havana, Cuba
| | - Ernst Urban
- Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse, 14, A-1090 Vienna, Austria
| | - Thierry Langer
- Department of Pharmaceutical Chemistry, University of Vienna , Althanstrasse, 14, A-1090 Vienna, Austria
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Pace V, Castoldi L, Mamuye AD, Langer T, Holzer W. Chemoselective Addition of Halomethyllithiums to Functionalized Isatins:A Straightforward Access to Spiro‐Epoxyoxindoles. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201500840] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Vittorio Pace
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, A‐1090 Vienna, Austria
| | - Laura Castoldi
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, A‐1090 Vienna, Austria
| | - Ashenafi Damtew Mamuye
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, A‐1090 Vienna, Austria
- University of Sassari, Department of Chemistry and Pharmacy, Via Vienna 2, I‐07100 Sassari, Italy
| | - Thierry Langer
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, A‐1090 Vienna, Austria
| | - Wolfgang Holzer
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, A‐1090 Vienna, Austria
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Mamuye AD, Castoldi L, Azzena U, Holzer W, Pace V. Chemoselective efficient synthesis of functionalized β-oxonitriles through cyanomethylation of Weinreb amides. Org Biomol Chem 2015; 13:1969-73. [DOI: 10.1039/c4ob02398f] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Homologation of Weinreb amides with cyanomethyllithium: a new route to β-oxonitriles.
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Affiliation(s)
- Ashenafi Damtew Mamuye
- Department of Pharmaceutical Chemistry
- University of Vienna
- Vienna
- Austria
- Department of Chemistry and Pharmacy
| | - Laura Castoldi
- Department of Pharmaceutical Chemistry
- University of Vienna
- Vienna
- Austria
| | - Ugo Azzena
- Department of Chemistry and Pharmacy
- University of Sassari
- Sassari
- Italy
| | - Wolfgang Holzer
- Department of Pharmaceutical Chemistry
- University of Vienna
- Vienna
- Austria
| | - Vittorio Pace
- Department of Pharmaceutical Chemistry
- University of Vienna
- Vienna
- Austria
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Degennaro L, Fanelli F, Giovine A, Luisi R. External Trapping of Halomethyllithium Enabled by Flow Microreactors. Adv Synth Catal 2014. [DOI: 10.1002/adsc.201400747] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pace V, Holzer W, Olofsson B. Increasing the Reactivity of Amides towards Organometallic Reagents: An Overview. Adv Synth Catal 2014. [DOI: 10.1002/adsc.201400630] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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