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Nicolai S, Waser J. (4+3) Annulation of Donor‐Acceptor Cyclopropanes and Azadienes: Highly Stereoselective Synthesis of Azepanones. Angew Chem Int Ed Engl 2022; 61:e202209006. [PMID: 35833420 PMCID: PMC9545371 DOI: 10.1002/anie.202209006] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Indexed: 12/17/2022]
Abstract
Azepanes are important seven‐membered heterocycles, which are present in numerous natural and synthetic compounds. However, the development of convergent synthetic methods to access them remains challenging. Herein, we report the Lewis acid catalyzed (4+3) annulative addition of aryl and amino donor‐acceptor cyclopropanes with 2‐aza‐1,3‐dienes. Densely substituted azepane derivatives were obtained in good to excellent yields and with high diastereoselectivity. The reaction occurred under mild conditions with ytterbium triflate as the catalyst. The use of copper triflate with a trisoxazoline (Tox) ligand led to an enantioselective transformation. The obtained cycloadducts were convenient substrates for a series of further modifications, showing the synthetic utility of these compounds.
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Affiliation(s)
- Stefano Nicolai
- Laboratory of Catalysis and Organic Synthesis Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne 1015 Lausanne Switzerland
| | - Jérôme Waser
- Laboratory of Catalysis and Organic Synthesis Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne 1015 Lausanne Switzerland
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2
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Lin YC, Schneider F, Eberle KJ, Chiodi D, Nakamura H, Reisberg SH, Chen J, Saito M, Baran PS. Atroposelective Total Synthesis of Darobactin A. J Am Chem Soc 2022; 144:14458-14462. [PMID: 35926121 PMCID: PMC9829381 DOI: 10.1021/jacs.2c05892] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A concise, modular synthesis of the novel antibiotic darobactin A is disclosed. The synthesis successfully forges the hallmark strained macrocyclic ring systems in a sequential fashion. Key transformations include two atroposelective Larock-based macrocyclizations, one of which proceeds with exquisite regioselectivity despite bearing an unprotected alkyne. The synthesis is designed with medicinal chemistry considerations in mind, appending key portions of the molecule at a late stage. Requisite unnatural amino acid building blocks are easily prepared in an enantiopure form using C-H activation and decarboxylative cross-coupling tactics.
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Affiliation(s)
- You-Chen Lin
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Fabian Schneider
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Kelly J Eberle
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Debora Chiodi
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Hugh Nakamura
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Solomon H Reisberg
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Jason Chen
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Masato Saito
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Phil S Baran
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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Ericson MD, Larson CM, Freeman KT, Nicke L, Geyer A, Haskell-Luevano C. Incorporation of Indoylated Phenylalanine Yields a Sub-Micromolar Selective Melanocortin-4 Receptor Antagonist Tetrapeptide. ACS OMEGA 2022; 7:27656-27663. [PMID: 35967074 PMCID: PMC9366794 DOI: 10.1021/acsomega.2c03307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/06/2022] [Indexed: 06/14/2023]
Abstract
The melanocortin family is involved in many physiological functions, including pigmentation, steroidogenesis, and appetite. The centrally expressed melanocortin-3 and melanocortin-4 receptors (MC3R and MC4R) possess overlapping but distinct roles in energy homeostasis. Herein, the third and fourth positions of a tetrapeptide lead compound [Ac-Arg-Arg-(pI)DPhe-Tic-NH2], previously reported to possess MC3R agonist and MC4R antagonist activities, were substituted with indoylated phenylalanine (Wsf/Wrf) residues in an attempt to generate receptor subtype selective compounds. At the third position, d-amino acids were required for melanocortin agonist activity, while both l- and d-residues resulted in MC4R antagonist activity. These results indicate that l-indoylated phenylalanine residues at the third position of the scaffold can generate MC4R over MC3R selective antagonist ligands, resulting in a substitution pattern that may be exploited for novel MC4R ligands that can be used to probe the in vivo activity of the MC4R without involvement of the MC3R.
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Affiliation(s)
- Mark D. Ericson
- Department
of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Courtney M. Larson
- Department
of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Katie T. Freeman
- Department
of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Lennart Nicke
- Faculty
of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, Marburg 35032, Germany
| | - Armin Geyer
- Faculty
of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, Marburg 35032, Germany
| | - Carrie Haskell-Luevano
- Department
of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Nicolai S, Waser J. (4+3) Annulation of Donor‐Acceptor Cyclopropanes and Azadienes: Highly Stereoselective Synthesis of Azepanones. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Stefano Nicolai
- EPFL ISIC: Ecole polytechnique federale de Lausanne Institut des Sciences et Ingenierie Chimiques SB ISIC EPFL SB ISIC LCSOBCH 4301 (Batochime UNIL)Av. F.-A. Forel 2 1015 Lausanne SWITZERLAND
| | - Jerome Waser
- EPFL: Ecole Polytechnique Federale de Lausanne SB, Institut des sciences et ingénierie chimiques EPFL SB ISIC LCSOBCH 4306 (Bât. BCH)Av. F.-A. Forel 2 1015 Lausanne SWITZERLAND
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5
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Fitzgerald LS, O'Duill ML. A Guide to Directing Group Removal: 8-Aminoquinoline. Chemistry 2021; 27:8411-8436. [PMID: 33559933 DOI: 10.1002/chem.202100093] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/08/2021] [Indexed: 12/23/2022]
Abstract
The use of directing groups allows high levels of selectivity to be achieved in transition metal-catalyzed transformations. Efficient removal of these auxiliaries after successful functionalization, however, can be very challenging. This review provides a critical overview of strategies used for removal of Daugulis' 8-aminoquinoline (2005-2020), one of the most widely used N,N-bidentate directing groups. The limitations of these strategies are discussed and alternative approaches are suggested for challenging substrates. Our aim is to provide a comprehensive end-users' guide for chemists in academia and industry who want to harness the synthetic power of directing groups-and be able to remove them from their final products.
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Affiliation(s)
- Liam S Fitzgerald
- School of Chemistry, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Miriam L O'Duill
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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Arbour CA, Mendoza LG, Stockdill JL. Recent advances in the synthesis of C-terminally modified peptides. Org Biomol Chem 2020; 18:7253-7272. [PMID: 32914156 PMCID: PMC9508648 DOI: 10.1039/d0ob01417f] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
C-Terminally modified peptides are important for the development and delivery of peptide-based pharmaceuticals because they impact peptide activity, stability, hydrophobicity, and membrane permeability. Additionally, the vulnerability of C-terminal esters to cleavage by endogenous esterases makes them excellent pro-drugs. Methods for post-SPPS C-terminal functionalization potentially enable access to libraries of modified peptides, facilitating tailoring of their solubility, potency, toxicity, and uptake pathway. Apparently minor structural changes can significantly impact the binding, folding, and pharmacokinetics of the peptide. This review summarizes developments in chemical methods for C-terminal modification of peptides published since the last review on this topic in 2003.
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Affiliation(s)
- Christine A Arbour
- Wayne State University, Department of Chemistry, Detroit, Michigan, USA.
| | - Lawrence G Mendoza
- Wayne State University, Department of Chemistry, Detroit, Michigan, USA.
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Nicke L, Horx P, Müller R, Els-Heindl S, Geyer A. Tryptophan Analogues with Fixed Side-Chain Orientation: Expanding the Scope. Chembiochem 2020; 22:330-335. [PMID: 33463878 PMCID: PMC7891422 DOI: 10.1002/cbic.202000424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/12/2020] [Indexed: 12/13/2022]
Abstract
A generalized synthetic strategy is proposed here for the synthesis of asymmetric β‐indoylated amino acids by 8‐aminoquinoline (8AQ)‐directed C(sp3)‐H functionalization of suitably protected precursors. Peptides containing one of the four stereoisomers of (indol‐3‐yl)‐3‐phenylalanine at position 2 of the parent peptide KwFwLL‐NH2 (w=d‐Trp) cover a wide range of activities as ghrelin receptor inverse agonists, among them the most active described until now. This application exemplarily shows how β‐indoylated amino acids can be used for the systematic variation of the position of an indole group in a bioactive peptide.
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Affiliation(s)
- Lennart Nicke
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Philip Horx
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Ronny Müller
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Sylvia Els-Heindl
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Armin Geyer
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
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Li X, Qi L, Li B, Zhao Z, He G, Chen G. Synthesis of Cyclophane-Braced Peptide Macrocycles via Palladium-Catalyzed Intramolecular C(sp3)–H Arylation of N-Methyl Alanine at C-Termini. Org Lett 2020; 22:6209-6213. [DOI: 10.1021/acs.orglett.0c02342] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Xinghua Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Liping Qi
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Bo Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Zhenxiang Zhao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Gang He
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Gong Chen
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
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Szostak M, Li G. Non-Classical Amide Bond Formation: Transamidation and Amidation of Activated Amides and Esters by Selective N–C/O–C Cleavage. SYNTHESIS-STUTTGART 2020. [DOI: 10.1055/s-0040-1707101] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In the past several years, tremendous advances have been made in non-classical routes for amide bond formation that involve transamidation and amidation reactions of activated amides and esters. These new methods enable the formation of extremely valuable amide bonds via transition-metal-catalyzed, transition-metal-free, or metal-free pathways by exploiting chemoselective acyl C–X (X = N, O) cleavage under mild conditions. In a broadest sense, these reactions overcome the formidable challenge of activating C–N/C–O bonds of amides or esters by rationally tackling nN → π*C=O delocalization in amides and nO → π*C=O donation in esters. In this account, we summarize the recent remarkable advances in the development of new methods for the synthesis of amides with a focus on (1) transition-metal/NHC-catalyzed C–N/C–O bond activation, (2) transition-metal-free highly selective cleavage of C–N/C–O bonds, (3) the development of new acyl-transfer reagents, and (4) other emerging methods.1 Introduction2 Transamidation of Amides2.1 Transamidation by Metal–NHC Catalysis (Pd–NHC, Ni–NHC)2.2 Transition-Metal-Free Transamidation via Tetrahedral Intermediates2.3 Reductive Transamidation2.4 New Acyl-Transfer Reagents2.5 Tandem Transamidations3 Amidation of Esters3.1 Amidation of Esters by Metal–NHC Catalysis (Pd–NHC, Ni–NHC)3.2 Transition-Metal-Free Amidation of Esters via Tetrahedral Intermediates3.3 Reductive Amidation of Esters4 Transamidations of Amides by Other Mechanisms5 Conclusions and Outlook
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Yang T, Chen X, Rao W, Koh MJ. Broadly Applicable Directed Catalytic Reductive Difunctionalization of Alkenyl Carbonyl Compounds. Chem 2020. [DOI: 10.1016/j.chempr.2019.12.026] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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11
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Nicke L, Müller R, Geyer A, Els-Heindl S. Side Chain Orientation of Tryptophan Analogues Determines Agonism and Inverse Agonism in Short Ghrelin Peptides. ChemMedChem 2019; 14:1849-1855. [PMID: 31442005 PMCID: PMC6899459 DOI: 10.1002/cmdc.201900409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/23/2019] [Indexed: 02/06/2023]
Abstract
We describe two synthetic amino acids with inverted side chain stereochemistry, which induce opposite biological activity. Phe4 is an important part of the activation motif of ghrelin, and in short peptide inverse agonists such as KwFwLL-NH2 , the aromatic core is necessary for inactivation of the receptor. To restrict indole/phenyl mobility and simultaneously strengthen the interaction between peptide and receptor, we exchanged the natural monoaryl amino acids for diaryl amino acids derived from tryptophan. By standard solid-phase peptide synthesis, each of them was inserted into ghrelin or in the aromatic core of the inverse agonist. Both ghrelin analogues showed nanomolar activity, indicating sufficient space to accommodate the additional side chain. In contrast, diaryl amino acids in the inverse agonist had considerable influence on receptor signaling. Whereas the introduction of Wsf maintains inverse agonism of the peptide, Wrf shifts the receptor more to active states and can induce agonism depending on its introduction site.
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Affiliation(s)
- Lennart Nicke
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Ronny Müller
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Armin Geyer
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Sylvia Els-Heindl
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
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