1
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Zhang B, Burchill L, Altalhi WAO, Ma HZ, O'Hair RAJ. A fixed-charge model of the N-protomer of 4-aminobenzoic acid to facilitate the study of the unimolecular and bimolecular chemistry of its "neutral" carboxylic acid group. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9681. [PMID: 38355884 DOI: 10.1002/rcm.9681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/24/2023] [Accepted: 11/25/2023] [Indexed: 02/16/2024]
Abstract
RATIONALE There are a growing number of examples of protomers formed via electrospray ionization (ESI) that do not fragment under mobile proton conditions, giving rise to distinct tandem mass spectra. To model the N-protomer of 4-aminobenzoic acid, here we study the gas-phase unimolecular and bimolecular chemistry of the 4-(carboxyphenyl)trimethylammonium ion. METHODS 4-(Carboxyphenyl)trimethylammonium iodide was synthesized, purified via recrystallization and transferred to the gas phase via ESI. 4-(Carboxyphenyl)trimethylammonium ion, 7, was mass selected and subjected to collision-induced dissociation and ion-molecule reactions in a linear ion trap mass spectrometer. RESULTS The major fragmentation channel for the fixed-charge cation 7 is methyl radical loss, whereas loss of trimethylamine and CO2 represents minor pathways. The free carboxylic acid functional group of 7 is unreactive toward a number of neutral reagents (methanol, acetone, acetonitrile, and N,N'-diisopropylcarbodiimide). 7 reacts very slowly with trimethylborate via addition-elimination, consistent with density functional theory (DFT) calculations that show this reaction is slightly endothermic. The deuterated cation 7(D) undergoes slow D/H exchange with ethanol, and DFT calculations reveal that a flip-flop mechanism operates. CONCLUSIONS The free carboxylic group of 7 is not very reactive toward neutral reagents in the gas phase.
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Affiliation(s)
- Beiang Zhang
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Laura Burchill
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Weam A O Altalhi
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- Department of Chemistry, Prince Sattam Bin Abdulaziz University, Hotat Bani Tamim, Saudi Arabia
| | - Howard Z Ma
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Richard A J O'Hair
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
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2
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Zhang J, Zhao H, Li G, Zhu X, Shang L, He Y, Liu X, Ma Y, Szostak M. Transamidation of thioamides with nucleophilic amines: thioamide N-C(S) activation by ground-state-destabilization. Org Biomol Chem 2022; 20:5981-5988. [PMID: 35441645 DOI: 10.1039/d2ob00412g] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Thioamides are 'single-atom' isosteres of amide bonds that have found broad applications in organic synthesis, biochemistry and drug discovery. In this New Talent themed issue, we present a general strategy for activation of N-C(S) thioamide bonds by ground-state-destabilization. This concept is outlined in the context of a full study on transamidation of thioamides with nucleophilic amines, and relies on (1) site-selective N-activation of the thioamide bond to decrease resonance and (2) highly chemoselective nucleophilic acyl addition to the thioamide CS bond. The follow-up collapse of the tetrahedral intermediate is favored by the electronic properties of the amine leaving group. The ground-state-destabilization concept of thioamides enables weakening of the N-C(S) bond and rationally modifies the properties of valuable thioamide isosteres for the development of new methods in organic synthesis. We fully expect that in analogy to the burgeoning field of destabilized amides introduced by our group in 2015, the thioamide bond ground-state-destabilization activation concept will find broad applications in various facets of chemical science, including metal-free, metal-catalyzed and metal-promoted reaction pathways.
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Affiliation(s)
- Jin Zhang
- College of Chemistry and Chemical Engineering, Key Laboratory of Chemical Additives for China National Light Industry, Shaanxi University of Science and Technology, Xi'an 710021, China. .,Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
| | - Hui Zhao
- College of Chemistry and Chemical Engineering, Key Laboratory of Chemical Additives for China National Light Industry, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Guangchen Li
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
| | - Xinhao Zhu
- College of Chemistry and Chemical Engineering, Key Laboratory of Chemical Additives for China National Light Industry, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Linqin Shang
- College of Chemistry and Chemical Engineering, Key Laboratory of Chemical Additives for China National Light Industry, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Yang He
- College of Chemistry and Chemical Engineering, Key Laboratory of Chemical Additives for China National Light Industry, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Xin Liu
- College of Chemistry and Chemical Engineering, Key Laboratory of Chemical Additives for China National Light Industry, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Yangmin Ma
- College of Chemistry and Chemical Engineering, Key Laboratory of Chemical Additives for China National Light Industry, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
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3
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Chen J, Lim JW, Ong DY, Chiba S. Iterative addition of carbon nucleophiles to N, N-dialkyl carboxamides for synthesis of α-tertiary amines. Chem Sci 2021; 13:99-104. [PMID: 35059156 PMCID: PMC8694388 DOI: 10.1039/d1sc05876b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 11/25/2021] [Indexed: 12/27/2022] Open
Abstract
A protocol for the synthesis of α-tertiary amines was developed by iterative addition of carbon nucleophiles to N,N-dialkyl carboxamides. Nucleophilic 1,2-addition of organolithium reagents to carboxamides forms anionic tetrahedral carbinolamine (hemiaminal) intermediates, which are subsequently treated with bromotrimethylsilane (Me3SiBr) followed by organomagnesium (Grignard) reagents, organolithium reagents or tetrabutylammonium cyanide, affording α-tertiary amines. Employment of (trimethylsilyl)methylmagnesium bromide as the 2nd nucleophile allowed for aza-Peterson olefination of the resulting α-tertiary (trimethylsilyl)methylamines with acidic work-up, resulting in the formation of 1,1-diarylethylenes.
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Affiliation(s)
- Jiahua Chen
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
| | - Jun Wei Lim
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
| | - Derek Yiren Ong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
| | - Shunsuke Chiba
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
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4
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An Easy Route to Aziridine Ketones and Carbinols. Int J Mol Sci 2021; 22:ijms222313145. [PMID: 34884949 PMCID: PMC8658269 DOI: 10.3390/ijms222313145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/28/2021] [Accepted: 12/02/2021] [Indexed: 11/20/2022] Open
Abstract
N,N-Dimethylaziridine-2-carboxamides react with organolithium reagents yielding 2-aziridinylketones. The reaction with one equivalent of organolithium compound is selective to amide carbonyl at a low (−78 °C) temperature. These ketones, in reaction with organolithium reagents, give symmetrical and unsymmetrical aziridinyl carbinols. The usage of excess phenyllithium may serve as a special N-Boc-protecting group cleavage method for acid-sensitive substrates.
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5
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Yang Y, Liu J, Kamounah FS, Ciancaleoni G, Lee JW. A CO 2-Catalyzed Transamidation Reaction. J Org Chem 2021; 86:16867-16881. [PMID: 34723529 DOI: 10.1021/acs.joc.1c02077] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Transamidation reactions are often mediated by reactive substrates in the presence of overstoichiometric activating reagents and/or transition metal catalysts. Here we report the use of CO2 as a traceless catalyst: in the presence of catalytic amounts of CO2, transamidation reactions were accelerated with primary, secondary, and tertiary amide donors. Various amine nucleophiles including amino acid derivatives were tolerated, showcasing the utility of transamidation in peptide modification and polymer degradation (e.g., Nylon-6,6). In particular, N,O-dimethylhydroxyl amides (Weinreb amides) displayed a distinct reactivity in the CO2-catalyzed transamidation versus a N2 atmosphere. Comparative Hammett studies and kinetic analysis were conducted to elucidate the catalytic activation mechanism of molecular CO2, which was supported by DFT calculations. We attributed the positive effect of CO2 in the transamidation reaction to the stabilization of tetrahedral intermediates by covalent binding to the electrophilic CO2.
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Affiliation(s)
- Yang Yang
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark
| | - Jian Liu
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark
| | - Fadhil S Kamounah
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark
| | - Gianluca Ciancaleoni
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, I-56124 Pisa, Italy.,CIRCC, via Celso Ulpiani 27, I-70126 Bari, Italy
| | - Ji-Woong Lee
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark.,Nanoscience Center, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark
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6
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Li G, Szostak M. Synthesis of biaryl ketones by arylation of Weinreb amides with functionalized Grignard reagents under thermodynamic control vs. kinetic control of N,N-Boc 2-amides. Org Biomol Chem 2021; 18:3827-3831. [PMID: 32396595 DOI: 10.1039/d0ob00813c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A highly efficient method for chemoselective synthesis of biaryl ketones by arylation of Weinreb amides (N-methoxy-N-methylamides) with functionalized Grignard reagents is reported. This protocol offers rapid entry to functionalized biaryl ketones after Mg/halide exchange with i-PrMgCl·LiCl under operationally-simple and practical reaction conditions. The scope of the method is highlighted in >40 examples, including bioactive compounds and pharmaceutical derivatives. Collectively, this transition-metal-free approach offers a major advantage over the recently established cross-coupling of amides by oxidative addition of N-C(O) bonds. Considering the utility of amide acylation reactions in modern synthesis, we expect that this method will be of broad interest.
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Affiliation(s)
- Guangchen Li
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
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7
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Ghinato S, Territo D, Maranzana A, Capriati V, Blangetti M, Prandi C. A Fast and General Route to Ketones from Amides and Organolithium Compounds under Aerobic Conditions: Synthetic and Mechanistic Aspects. Chemistry 2021; 27:2868-2874. [PMID: 33150980 DOI: 10.1002/chem.202004840] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Indexed: 12/11/2022]
Abstract
We report that the nucleophilic acyl substitution reaction of aliphatic and (hetero)aromatic amides by organolithium reagents proceeds quickly (20 s reaction time), efficiently, and chemoselectively with a broad substrate scope in the environmentally responsible cyclopentyl methyl ether, at ambient temperature and under air, to provide ketones in up to 93 % yield with an effective suppression of the notorious over-addition reaction. Detailed DFT calculations and NMR investigations support the experimental results. The described methodology was proven to be amenable to scale-up and recyclability protocols. Contrasting classical procedures carried out under inert atmospheres, this work lays the foundation for a profound paradigm shift of the reactivity of carboxylic acid amides with organolithiums, with ketones being straightforwardly obtained by simply combining the reagents under aerobic conditions and with no need of using previously modified or pre-activated amides, as recommended.
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Affiliation(s)
- Simone Ghinato
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125, Torino, Italy
| | - Davide Territo
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125, Torino, Italy
| | - Andrea Maranzana
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125, Torino, Italy
| | - Vito Capriati
- Dipartimento di Farmacia-Scienze del Farmaco, Università di Bari Aldo Moro, Consorzio CINMPIS, Via E. Orabona 4, 70125, Bari, Italy
| | - Marco Blangetti
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125, Torino, Italy
| | - Cristina Prandi
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125, Torino, Italy
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8
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Miyoshi N, Kimura S, Kubo S, Ohmura SD, Ueno M. Chemoselective Ketone Synthesis by the Strontium‐mediated Alkylation or Arylation of
N
,
N
‐Dimethylamides or Urea. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.202000389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Norikazu Miyoshi
- Department of Natural Science Graduate School of Advanced Technology and Science Tokushima University 2-1 Minami-jousanjima Tokushima 770-8506 Japan
- Department of Chemistry Faculty of Integrated Arts and Sciences Tokushima University 1-1 Minami-jousanjima Tokushima 770-8502 Japan
| | - Shodai Kimura
- Department of Chemistry Faculty of Integrated Arts and Sciences Tokushima University 1-1 Minami-jousanjima Tokushima 770-8502 Japan
| | - Shigeki Kubo
- Department of Chemistry Faculty of Integrated Arts and Sciences Tokushima University 1-1 Minami-jousanjima Tokushima 770-8502 Japan
| | - Satoshi D. Ohmura
- Department of Natural Science Graduate School of Advanced Technology and Science Tokushima University 2-1 Minami-jousanjima Tokushima 770-8506 Japan
- Department of Chemistry Faculty of Integrated Arts and Sciences Tokushima University 1-1 Minami-jousanjima Tokushima 770-8502 Japan
- Present address: National Institute of Technology Niihama College
| | - Masaharu Ueno
- Department of Natural Science Graduate School of Advanced Technology and Science Tokushima University 2-1 Minami-jousanjima Tokushima 770-8506 Japan
- Department of Chemistry Faculty of Integrated Arts and Sciences Tokushima University 1-1 Minami-jousanjima Tokushima 770-8502 Japan
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9
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Li G, Szostak M. Kinetically Controlled, Highly Chemoselective Acylation of Functionalized Grignard Reagents with Amides by N−C Cleavage. Chemistry 2019; 26:611-615. [DOI: 10.1002/chem.201904678] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/05/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Guangchen Li
- Department of ChemistryRutgers University 73 Warren Street Newark NJ 07102 USA
| | - Michal Szostak
- Department of ChemistryRutgers University 73 Warren Street Newark NJ 07102 USA
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10
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Li G, Szostak M. Transition-Metal-Free Activation of Amides by N-C Bond Cleavage. CHEM REC 2019; 20:649-659. [PMID: 31833633 DOI: 10.1002/tcr.201900072] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 12/11/2022]
Abstract
The amide bond N-C activation represents a powerful strategy in organic synthesis to functionalize the historically inert amide linkage. This personal account highlights recent remarkable advances in transition-metal-free activation of amides by N-C bond cleavage, focusing on both (1) mechanistic aspects of ground-state-destabilization of the amide bond enabling formation of tetrahedral intermediates directly from amides with unprecedented selectivity, and (2) synthetic utility of the developed transformations. Direct nucleophilic addition to amides enables a myriad of powerful methods for the formation of C-C, C-N, C-O and C-S bonds, providing a straightforward and more synthetically useful alternative to acyl-metals.
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Affiliation(s)
- Guangchen Li
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, United States
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, United States
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11
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Ghinato S, Dilauro G, Perna FM, Capriati V, Blangetti M, Prandi C. Directed ortho-metalation-nucleophilic acyl substitution strategies in deep eutectic solvents: the organolithium base dictates the chemoselectivity. Chem Commun (Camb) 2019; 55:7741-7744. [PMID: 31168546 DOI: 10.1039/c9cc03927a] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Directed ortho metalation (DoM) or nucleophilic acyl substitution (SNAc) can be efficiently programmed on the same aromatic carboxylic acid amide, in a choline chloride-based eutectic mixture, by simply switching the nature of the organolithium reagent. Telescoped, one-pot ortho-lithiation/Suzuki-Miyaura cross-couplings have also been demonstrated for the first time in Deep Eutectic Solvents.
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Affiliation(s)
- Simone Ghinato
- Dipartimento di Chimica, Università di Torino, Via P. Giuria 7, I-10125 Torino, Italy.
| | - Giuseppe Dilauro
- Dipartimento di Farmacia-Scienze del Farmaco, Università di Bari "A. Moro", Consorzio C.I.N.M.P.I.S., Via E. Orabona 4, I-70125 Bari, Italy.
| | - Filippo Maria Perna
- Dipartimento di Farmacia-Scienze del Farmaco, Università di Bari "A. Moro", Consorzio C.I.N.M.P.I.S., Via E. Orabona 4, I-70125 Bari, Italy.
| | - Vito Capriati
- Dipartimento di Farmacia-Scienze del Farmaco, Università di Bari "A. Moro", Consorzio C.I.N.M.P.I.S., Via E. Orabona 4, I-70125 Bari, Italy.
| | - Marco Blangetti
- Dipartimento di Chimica, Università di Torino, Via P. Giuria 7, I-10125 Torino, Italy.
| | - Cristina Prandi
- Dipartimento di Chimica, Università di Torino, Via P. Giuria 7, I-10125 Torino, Italy.
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12
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de Jong J, Heijnen D, Helbert H, Feringa BL. One-pot, modular approach to functionalized ketones via nucleophilic addition/Buchwald-Hartwig amination strategy. Chem Commun (Camb) 2019; 55:2908-2911. [PMID: 30785130 DOI: 10.1039/c8cc08444k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A general one-pot procedure for the 1,2-addition of organolithium reagents to amides followed by the Buchwald-Hartwig amination with in situ released lithium amides is presented. In this work amides are used as masked ketones, revealed by the addition of organolithium reagents which generates a lithium amide, suitable for subsequent Buchwald-Hartwig coupling in the presence of a palladium catalyst. This methodology allows for rapid, efficient and atom economic synthesis of aminoarylketones in good yields.
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Affiliation(s)
- Jorn de Jong
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
| | - Dorus Heijnen
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
| | - Hugo Helbert
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
| | - Ben L Feringa
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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13
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Meng G, Shi S, Lalancette R, Szostak R, Szostak M. Reversible Twisting of Primary Amides via Ground State N-C(O) Destabilization: Highly Twisted Rotationally Inverted Acyclic Amides. J Am Chem Soc 2018; 140:727-734. [PMID: 29240413 DOI: 10.1021/jacs.7b11309] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Since the seminal studies by Pauling in 1930s, planarity has become the defining characteristic of the amide bond. Planarity of amides has central implications for the reactivity and chemical properties of amides of relevance to a range of chemical disciplines. While the vast majority of amides are planar, nonplanarity has a profound effect on the properties of the amide bond, with the most common method to restrict the amide bond relying on the incorporation of the amide function into a rigid cyclic ring system. In a major departure from this concept, here, we report the first class of acyclic twisted amides that can be prepared, reversibly, from common primary amides in a single, operationally trivial step. Di-tert-butoxycarbonylation of the amide nitrogen atom yields twisted amides in which the amide bond exhibits nearly perpendicular twist. Full structural characterization of a range of electronically diverse compounds from this new class of twisted amides is reported. Through reactivity studies we demonstrate unusual properties of the amide bond, wherein selective cleavage of the amide bond can be achieved by a judicious choice of the reaction conditions. Through computational studies we evaluate structural and energetic details pertaining to the amide bond deformation. The ability to selectively twist common primary amides, in a reversible manner, has important implications for the design and application of the amide bond nonplanarity in structural chemistry, biochemistry and organic synthesis.
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Affiliation(s)
- Guangrong Meng
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Shicheng Shi
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Roger Lalancette
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Roman Szostak
- Department of Chemistry, Wroclaw University , F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Michal Szostak
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
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14
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Das R, Kumar GS, Kapur M. Amides as Weak Coordinating Groups in Proximal C-H Bond Activation. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700546] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Riki Das
- Department of Chemistry; Indian Institute of Science Education and Research Bhopal; Bhopal Bypass Road, Bhauri 462066 Bhopal MP India
| | - Gangam Srikanth Kumar
- Department of Chemistry; Indian Institute of Science Education and Research Bhopal; Bhopal Bypass Road, Bhauri 462066 Bhopal MP India
| | - Manmohan Kapur
- Department of Chemistry; Indian Institute of Science Education and Research Bhopal; Bhopal Bypass Road, Bhauri 462066 Bhopal MP India
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15
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Castoldi L, Holzer W, Langer T, Pace V. Evidence and isolation of tetrahedral intermediates formed upon the addition of lithium carbenoids to Weinreb amides and N-acylpyrroles. Chem Commun (Camb) 2017; 53:9498-9501. [DOI: 10.1039/c7cc05215d] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Trapping tetrahedral intermediates from Weinreb amides andN-acylpyrroles.
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Affiliation(s)
- Laura Castoldi
- University of Vienna – Department of Pharmaceutical Chemistry
- Vienna
- Austria
| | - Wolfgang Holzer
- University of Vienna – Department of Pharmaceutical Chemistry
- Vienna
- Austria
| | - Thierry Langer
- University of Vienna – Department of Pharmaceutical Chemistry
- Vienna
- Austria
| | - Vittorio Pace
- University of Vienna – Department of Pharmaceutical Chemistry
- Vienna
- Austria
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16
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Abbasov ME, Hudson BM, Tantillo DJ, Romo D. Stereodivergent, Diels-Alder-initiated organocascades employing α,β-unsaturated acylammonium salts: scope, mechanism, and application. Chem Sci 2016; 8:1511-1524. [PMID: 28616147 PMCID: PMC5460596 DOI: 10.1039/c6sc04273b] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 10/24/2016] [Indexed: 12/16/2022] Open
Abstract
Chiral α,β-unsaturated acylammonium salts are novel dienophiles enabling enantioselective Diels–Alder-lactonization (DAL) organocascades leading to cis- and trans-fused, bicyclic γ- and δ-lactones.
Chiral α,β-unsaturated acylammonium salts are novel dienophiles enabling enantioselective Diels–Alder-lactonization (DAL) organocascades leading to cis- and trans-fused, bicyclic γ- and δ-lactones from readily prepared dienes, commodity acid chlorides, and a chiral isothiourea organocatalyst under mild conditions. We describe extensions of stereodivergent DAL organocascades to other racemic dienes bearing pendant secondary and tertiary alcohols, and application to a formal synthesis of (+)-dihydrocompactin is described. A combined experimental and computational investigation of unsaturated acylammonium salt formation and the entire DAL organocascade pathway provide a rationalization of the effect of Brønsted base additives and enabled a controllable, diastereodivergent DAL process leading to a full complement of possible stereoisomeric products. Evaluation of free energy and enthalpy barriers in conjunction with experimentally observed temperature effects revealed that the DAL is a rare case of an entropy-controlled diastereoselective process. NMR analysis of diene alcohol–Brønsted base interactions and computational studies provide a plausible explanation of observed stabilization of exo transition-state structures through hydrogen-bonding effects.
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Affiliation(s)
- Mikail E Abbasov
- Department of Chemistry and Biochemistry , Baylor University , One Bear Place 97348 , Waco , Texas 76798 , USA
| | - Brandi M Hudson
- Department of Chemistry , University of California-Davis , One Shields Avenue , Davis , California 95616 , USA .
| | - Dean J Tantillo
- Department of Chemistry , University of California-Davis , One Shields Avenue , Davis , California 95616 , USA .
| | - Daniel Romo
- Department of Chemistry and Biochemistry , Baylor University , One Bear Place 97348 , Waco , Texas 76798 , USA
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17
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Das R, Kapur M. Product Control using Substrate Design: Ruthenium-Catalysed Oxidative C−H Olefinations of Cyclic Weinreb Amides. Chemistry 2016; 22:16986-16990. [DOI: 10.1002/chem.201603126] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Riki Das
- Department of Chemistry; Indian Institute of Science Education and Research Bhopal; Bhopal Bypass Road, Bhauri Bhopal 462066, MP India
| | - Manmohan Kapur
- Department of Chemistry; Indian Institute of Science Education and Research Bhopal; Bhopal Bypass Road, Bhauri Bhopal 462066, MP India
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18
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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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19
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Liu C, Achtenhagen M, Szostak M. Chemoselective Ketone Synthesis by the Addition of Organometallics to N-Acylazetidines. Org Lett 2016; 18:2375-8. [DOI: 10.1021/acs.orglett.6b00842] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Chengwei Liu
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Marcel Achtenhagen
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Michal Szostak
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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20
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Zhang MZ, Guo QH, Sheng WB, Guo CC. Potassiumtert-Butoxide-Mediated Amine Acyl Exchange Reaction ofN,N-Disubstituted Formamides with Aromatic Carbonyl DerivativesviaSequential CN Bond Cleavage/Formation: an Approach to Aromatic Amides. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500551] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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21
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Szostak R, Aubé J, Szostak M. Determination of Structures and Energetics of Small- and Medium-Sized One-Carbon-Bridged Twisted Amides using ab Initio Molecular Orbital Methods: Implications for Amidic Resonance along the C–N Rotational Pathway. J Org Chem 2015; 80:7905-27. [DOI: 10.1021/acs.joc.5b00881] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roman Szostak
- Department of Chemistry, Wroclaw University, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Jeffrey Aubé
- Division of Chemical
Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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22
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Xu Z, Wang Q, Zhu J. Total Syntheses of (-)-Mersicarpine, (-)-Scholarisine G, (+)-Melodinine E, (-)-Leuconoxine, (-)-Leuconolam, (-)-Leuconodine A, (+)-Leuconodine F, and (-)-Leuconodine C: Self-Induced Diastereomeric Anisochronism (SIDA) Phenomenon for Scholarisine G and Leuconodines A and C. J Am Chem Soc 2015; 137:6712-24. [PMID: 25946614 DOI: 10.1021/jacs.5b03619] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Enantioselective total syntheses of title natural products from a common cyclohexenone derivative (S)-18 were reported. Ozonolysis of (S)-18 afforded a stable diketo ester (R)-17 that was subsequently converted to two skeletally different natural products, i.e., (-)-mersicarpine (8) with a [6.5.6.7] fused tetracyclic ring system and (-)-scholarisine G (9) with a [6.5.6.6.5] fused pentacyclic skeleton, respectively. The postcyclization diversification was realized by taking advantage of the facile conversion of (+)-melodinine E (6) to N-acyliminium ion 7, from which a hydroxy group was selectively introduced to the C6, C7, C10 and the central C21 position of diazafenestrane system, leading to (-)-leuconodine A (11), (+)-leuconodine F (12), (-)-scholarisine G (9), (-)-leuconodine C (13), and skeletally different (-)-leuconolam (5). Furthermore, an unprecedented non-natural oxabridged oxadiazafenestrane 68 was formed by oxidation of (+)-melodinine E (6). During the course of this study, a strong self-induced diastereomeric anisochronism (SIDA) phenomenon was observed for scholarisine G (9), leuconodines A (11) and C (13). X-ray structures of both the racemic and the enantiopure natural products 9, 11, and 13 were obtained. The different crystal packing of these two forms nicely explained the chemical shift differences observed in the (1)H NMR spectra of the racemic and the enantio-enriched compounds in an achiral environment.
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Affiliation(s)
- Zhengren Xu
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH5304, CH-1015 Lausanne, Switzerland
| | - Qian Wang
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH5304, CH-1015 Lausanne, Switzerland
| | - Jieping Zhu
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH5304, CH-1015 Lausanne, Switzerland
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23
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Plessel KN, Jones AC, Wherritt DJ, Maksymowicz RM, Poweleit E, Reich HJ. A Rapid Injection NMR Study of the Reaction of Organolithium Reagents with Esters, Amides, and Ketones. Org Lett 2015; 17:2310-3. [DOI: 10.1021/acs.orglett.5b00650] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kristin N. Plessel
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Amanda C. Jones
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel J. Wherritt
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Rebecca M. Maksymowicz
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - EricT. Poweleit
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Hans J. Reich
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
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24
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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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25
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Anti-Markovnikov stereoselective addition of bis(trimethylsilyl)octadiene to ketal obtained by unprecedented retro-Claisen condensation of 3-hydroxy-2,4-pentanedione bis-ketal. CR CHIM 2014. [DOI: 10.1016/j.crci.2014.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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26
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Davies SG, Fletcher AM, Thomson JE. Direct asymmetric syntheses of chiral aldehydes and ketones via N-acyl chiral auxiliary derivatives including chiral Weinreb amide equivalents. Chem Commun (Camb) 2014; 49:8586-98. [PMID: 23959006 DOI: 10.1039/c3cc45463k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This article covers N-acyl chiral auxiliary-based approaches to the asymmetric synthesis of enantiopure aldehydes and ketones. The use of diastereoisomerically pure N-acyl derivatives of chiral auxiliaries (including chiral Weinreb amide equivalents) and their conversion to the corresponding enantiopure aldehydes and ketones in a single synthetic operation by treatment with a hydride reducing agent or an organometallic reagent, respectively, are highlighted.
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Affiliation(s)
- Stephen G Davies
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
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27
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Szostak M, Sautier B, Procter DJ. Structural analysis and reactivity of unusual tetrahedral intermediates enabled by SmI2-mediated reduction of barbituric acids: vinylogous N-acyliminium additions to α-hydroxy-N-acyl-carbamides. Chem Commun (Camb) 2014; 50:2518-21. [DOI: 10.1039/c3cc48932a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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28
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Szostak M, Sautier B, Spain M, Behlendorf M, Procter DJ. Selective reduction of barbituric acids using SmI2/H2O: synthesis, reactivity, and structural analysis of tetrahedral adducts. Angew Chem Int Ed Engl 2013; 52:12559-63. [PMID: 24123558 PMCID: PMC4065343 DOI: 10.1002/anie.201306484] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Michal Szostak
- School of Chemistry, University of ManchesterOxford Road, Manchester M13 9PL (UK)
| | - Brice Sautier
- School of Chemistry, University of ManchesterOxford Road, Manchester M13 9PL (UK)
| | | | | | - David J Procter
- School of Chemistry, University of ManchesterOxford Road, Manchester M13 9PL (UK)
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29
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Szostak M, Sautier B, Spain M, Behlendorf M, Procter DJ. Selective Reduction of Barbituric Acids Using SmI2/H2O: Synthesis, Reactivity, and Structural Analysis of Tetrahedral Adducts. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201306484] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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30
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Os'kina IA. Transesterification Kinetics Investigation of R-Substituted Phenyl Benzoates with 4-Methoxyphenol in the Presence of K2
CO3
in DMF. INT J CHEM KINET 2013. [DOI: 10.1002/kin.20822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Irina A. Os'kina
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry; Siberian Branch of Russian Academy of Sciences; Novosibirsk 630090 Russian Federation
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31
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Affiliation(s)
- Michal Szostak
- Department of Medicinal Chemistry, University of Kansas, Delbert M. Shankel Structural Biology Center, 2034 Becker Drive, Lawrence, Kansas 66047
| | - Jeffrey Aubé
- Department of Medicinal Chemistry, University of Kansas, Delbert M. Shankel Structural Biology Center, 2034 Becker Drive, Lawrence, Kansas 66047
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32
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Gómez-Bombarelli R, Calle E, Casado J. Mechanisms of lactone hydrolysis in neutral and alkaline conditions. J Org Chem 2013; 78:6868-79. [PMID: 23758295 DOI: 10.1021/jo400258w] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The neutral and base-catalyzed hydrolysis of nine carboxylic acid esters was studied using a hybrid supermolecule-PCM approach including six explicit water molecules. The molecules studied included two linear esters, four β-lactones, two γ-lactones, and one δ-lactone: ethyl acetate and methyl formate, β-propiolactone, β-butyrolactone, β-isovalerolactone, diketene (4-methyleneoxetan-2-one), γ-butyrolactone, 2(5H)-furanone, and δ-valerolactone. DFT and ab initio methods were used to analyze the features of the various possible hydrolysis mechanisms. For all compounds, reasonable to very good qualitative and quantitative agreement with experimental work was found, and evidence is provided to support long-standing hypotheses regarding the role of solvent molecule as a base catalyst. In addition, novel evidence is presented for the existence of an elimination-addition mechanism in the basic hydrolysis of diketene. A parallel work addresses the acid-catalyzed hydrolysis of lactones.
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Affiliation(s)
- Rafael Gómez-Bombarelli
- Department of Physics, School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS, Edinburgh, United Kingdom
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33
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Mola L, Font J, Bosch L, Caner J, Costa AM, Etxebarría-Jardí G, Pineda O, de Vicente D, Vilarrasa J. Nucleophile-catalyzed additions to activated triple bonds. Protection of lactams, imides, and nucleosides with MocVinyl and related groups. J Org Chem 2013; 78:5832-42. [PMID: 23713491 DOI: 10.1021/jo4006409] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Additions of lactams, imides, (S)-4-benzyl-1,3-oxazolidin-2-one, 2-pyridone, pyrimidine-2,4-diones (AZT derivatives), or inosines to the electron-deficient triple bonds of methyl propynoate, tert-butyl propynoate, 3-butyn-2-one, N-propynoylmorpholine, or N-methoxy-N-methylpropynamide in the presence of many potential catalysts were examined. DABCO and, second, DMAP appeared to be the best (highest reaction rates and E/Z ratios), while RuCl3, RuClCp*(PPh3)2, AuCl, AuCl(PPh3), CuI, and Cu2(OTf)2 were incapable of catalyzing such additions. The groups incorporated (for example, the 2-(methoxycarbonyl)ethenyl group that we name MocVinyl) serve as protecting groups for the above-mentioned heterocyclic CONH or CONHCO moieties. Deprotections were accomplished via exchange with good nucleophiles: the 1-dodecanethiolate anion turned out to be the most general and efficient reagent, but in some particular cases other nucleophiles also worked (e.g., MocVinyl-inosines can be cleaved with succinimide anion). Some structural and mechanistic details have been accounted for with the help of DFT and MP2 calculations.
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Affiliation(s)
- Laura Mola
- Departament de Química Orgànica, Facultat de Química, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Catalonia, Spain
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34
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Vlasov VM. Substituent effects on the activation parameters of pyridine acylation with esters and thioesters in solution. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2013. [DOI: 10.1134/s1070428013030135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Vlasov VM. Towards mechanisms of bimolecular nucleophilic reactions in solution-probing the variation of the activation parameters in the reactions of aromatic compounds. J PHYS ORG CHEM 2011. [DOI: 10.1002/poc.1912] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Vladislav M. Vlasov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry; Siberian Branch of the Russian Academy of Sciences; 630090 Novosibirsk Lavrentjev Ave., 9 Russia
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36
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Khalfina IA, Vlasov VM. Enthalpy-entropy correlations in reactions of 2,4-dinitrophenyl benzoate with phenols in the presence of potassium hydrogen carbonate and with potassium phenoxides in dimethylformamide. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2011. [DOI: 10.1134/s1070428011060030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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37
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Nguyen H, Ma G, Gladysheva T, Fremgen T, Romo D. Bioinspired total synthesis and human proteasome inhibitory activity of (-)-salinosporamide A, (-)-homosalinosporamide A, and derivatives obtained via organonucleophile promoted bis-cyclizations. J Org Chem 2011; 76:2-12. [PMID: 21047113 PMCID: PMC5546919 DOI: 10.1021/jo101638r] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A full account of concise, enantioselective syntheses of the anticancer agent (-)-salinosporamide A and derivatives, including (-)-homosalinosporamide, that was inspired by biosynthetic considerations is described. The brevity of the synthetic strategy stems from a key bis-cyclization of a β-keto tertiary amide, which retains optical purity enabled by A(1,3)-strain rendering slow epimerization relative to the rate of bis-cyclization. Optimization studies of the key bis-cyclization, enabled through byproduct isolation and characterization, are described that ultimately allowed for a gram scale synthesis of a versatile bicyclic core structure with a high degree of stereoretention. An optimized procedure for zincate generation by the method of Knochel, generally useful for the synthesis of salino A derivatives, led to dramatic improvements in side-chain attachment and a novel diastereomer of salino A. The versatility of the described strategy is demonstrated by the synthesis of designed derivatives including (-)-homosalinosporamide A. Inhibition of the human 20S and 26S proteasome by these derivatives using an enzymatic assay are also reported. The described total synthesis of salino A raises interesting questions regarding how biosynthetic enzymes leading to the salinosporamides proceeding via optically active β-keto secondary amides, are able to maintain the stereochemical integrity at the labile C2 stereocenter or if a dynamic kinetic resolution is operative.
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Affiliation(s)
- Henry Nguyen
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, USA
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38
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Abstract
Medium-bridged twisted lactams, in which a non-planar amide bond is achieved by incorporating the nitrogen atom at the bridgehead position in a medium-sized heterocycle, offer an attractive setting in which to study the properties of distorted amide linkages. This Emerging Area article will describe progress in the preparation and study of these compounds. This work shows that compounds containing an even moderately distorted amide bond display useful and unusual chemical properties while retaining a measure of stability that enables their study.
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Affiliation(s)
- Michal Szostak
- Department of Medicinal Chemistry, University of Kansas, Structural Biology Center, 2121 Simons Drive, West Campus, Lawrence, KS 66047, USA
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39
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Moraleda D, Santelli M. Enantio-differentiating reactions of a racemic γ
-lactone enolate with chiral esters. A DFT investigation. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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40
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Szostak M, Aubé J. Synthesis, structural analysis, and reactivity of bridged orthoamides by intramolecular Schmidt reaction. J Am Chem Soc 2010; 132:2530-1. [PMID: 20128606 DOI: 10.1021/ja910654t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Intramolecular Schmidt reactions can be reliably steered toward bridged heterocycles containing orthoamides in high yields. The ketal tether enhances the control of regioselectivity in the migration of the bond distal to the reactive azide nucleophile, thus providing the first examples of the intramolecular Schmidt reaction proceeding with a complete regioselectivity en route to bridged products. The method is broad in scope and allows for systematic study of compounds that are analogous to elusive tetrahedral intermediates of amide addition reactions. Some initial reactivity and structural profiling of these compounds are also reported.
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Affiliation(s)
- Michal Szostak
- Department of Medicinal Chemistry, University of Kansas, Structural Biology Center, 2121 Simons Drive, West Campus, Lawrence, Kansas 66047, USA
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41
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Os’kina IA, Vlasov VM. Effect of nucleophile on the activation parameters of transesterification of 4-nitrophenyl benzoates. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2010. [DOI: 10.1134/s1070428010030048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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42
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Szostak M, Yao L, Aubé J. Proximity effects in nucleophilic addition reactions to medium-bridged twisted lactams: remarkably stable tetrahedral intermediates. J Am Chem Soc 2010; 132:2078-84. [PMID: 20095610 PMCID: PMC2820158 DOI: 10.1021/ja909792h] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reactions of a series of strained bicyclic and tricyclic one-carbon bridged lactams with organometallic reagents have been investigated. These amides permit isolation of a number of remarkably stable hemiaminals upon nucleophilic addition to the twisted amide bonds present in the lactam precursors. The factors that affect the stability of the resulting bridged hemiaminals are presented. In some cases, the hemiaminals were found to collapse to the open-form amino ketones in a manner expected for traditional carboxylic acid derivatives. Transannular N...C=O interactions were also observed in some nine-membered amino ketones. Additionally, tricyclic bridged lactams were found to react with some nucleophiles that typically react with ketones but not with planar amides. The effect of geometry on the reactivity of amide bonds and the amide bond distortion range that marks the boundary of amide-like and ketone-like carbonyl reactivity of lactams are also discussed.
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Affiliation(s)
- Michal Szostak
- Department of Medicinal Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Malott Hall, Room 4070, Lawrence, Kansas 66045-7852
| | - Lei Yao
- Department of Medicinal Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Malott Hall, Room 4070, Lawrence, Kansas 66045-7852
| | - Jeffrey Aubé
- Department of Medicinal Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Malott Hall, Room 4070, Lawrence, Kansas 66045-7852
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43
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Vlasov VM. Effects of substituents on activation parameters in the reactions of carboxylic acid derivatives with anionic and neutral nucleophiles. NEW J CHEM 2009. [DOI: 10.1039/b808115h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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44
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Khalfina IA, Vlasov VM. Enthalpy and entropy relations in reactions of 2,4-dinitrophenyl benzoate with phenols in the presence of potassium carbonate in dimethylformamide. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2008. [DOI: 10.1134/s1070428008110092] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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45
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Rosenberg RE. Addition of Anions to Carbonyl Compounds: An Ab Initio Study. J Org Chem 2008; 73:6636-41. [DOI: 10.1021/jo800664k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert Evan Rosenberg
- Transylvania University, Department of Chemistry, 300 North Broadway, Lexington, Kentucky 40508
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46
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Os’kina IA, Vlasov VM. Kinetics of the reaction of substituted 4-nitrophenyl benzoates with benzenethiol in the presence of potassium carbonate in dimethylformamide. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2008. [DOI: 10.1134/s1070428008040167] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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47
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Pippel DJ, Mapes CM, Mani NS. Reactions between Weinreb amides and 2-magnesiated oxazoles: a simple and efficient preparation of 2-acyl oxazoles. J Org Chem 2007; 72:5828-31. [PMID: 17585818 DOI: 10.1021/jo070646a] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Treatment of oxazole or 5-aryl oxazoles with i-PrMgCl smoothly generates the corresponding 2-Grignard reagents, which react with Weinreb amides to provide exclusively 2-acyl oxazole products.
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Affiliation(s)
- Daniel J Pippel
- Johnson & Johnson Pharmaceutical Research and Development, L.L.C., 3210 Merryfield Row, San Diego, CA 92121, USA.
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Henry-Riyad H, Lee C, Purohit VC, Romo D. Bicyclic- and Tricyclic-β-lactones via Organonucleophile-Promoted Bis-Cyclizations of Keto Acids: Enantioselective Synthesis of (+)-Dihydroplakevulin. Org Lett 2006; 8:4363-6. [PMID: 16956227 DOI: 10.1021/ol061816t] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A highly diastereoselective, nucleophile-promoted bis-cyclization process, employing readily available and tractable keto acid substrates, is described. This methodology provides concise access to bicyclic- and tricyclic-beta-lactones bearing tertiary carbinol centers and quaternary carbons, greatly extending the scope of previous routes to bicyclic-beta-lactones from aldehyde acid substrates. The utility of the method was demonstrated by application to an enantioselective synthesis of (+)-dihydroplakevulin A. This and related processes may be revealing a subtle interplay between [2+2] cycloaddition and nucleophile-catalyzed aldol lactonization (NCAL) reaction manifolds.
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Affiliation(s)
- Huda Henry-Riyad
- Department of Chemistry, PO Box 30012, Texas A&M University, College Station, Texas 77842-3012, USA
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Abstract
Additions of lithium phenylacetylide to a Weinreb amide are described. Dimeric lithium acetylide reacts via a monosolvated monomer-based transition structure. The robust tetrahedral intermediate forms sequentially a C(1) 2:2 mixed tetramer with the excess lithium acetylide and a 1:3 (alkoxide-rich) mixed tetramer. The stabilities of the mixed tetramers are consistent with a pronounced autoinhibition.
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Affiliation(s)
- Bo Qu
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853-1301, USA
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Hanusek J, Sedlák M, Jansa P, Štěrba V. Study of ring closure reaction of substituted phenylN-(2-thiocarbamoylphenyl)carbamates catalysed by methoxide ion. J PHYS ORG CHEM 2006. [DOI: 10.1002/poc.999] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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