1
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Keyes ED, Mifflin MC, Austin MJ, Sandres J, Roberts AG. Chemical cyclization of tyrosine-containing peptides via in situ generated triazolinedione peptides. Methods Enzymol 2024; 698:89-109. [PMID: 38886041 DOI: 10.1016/bs.mie.2024.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Tyr-derived cyclic peptide natural products are formed by enzymatic manifolds that oxidatively cross-link embedded phenolic side chains of tyrosine (Tyr) and 4-hydroxyphenylglycine residues during their controlled production. Bioactive Tyr-derived cyclic peptides, such as the arylomycins and vancomycins, continue to motivate the development of enzymatic and chemical strategies for their de novo assembly and modification. However, chemical access to these structurally diverse natural cycles can be challenging and step intensive. Therefore, we developed an oxidative procedure to selectively convert Tyr-containing N4-substituted 1,2,4-triazolidine-3,5-dione peptides (urazole peptides) into stable Tyr-linked cyclic peptides. We show that Tyr-containing urazole peptides are simple to prepare and convert into reactive N4-substituted 1,2,4-triazoline-3,5-dione peptides by oxidation, which then undergo spontaneous cyclization under mildly basic aqueous conditions to form a cross-linkage with the phenol side chain of embedded Tyr residues. Using this approach, we have demonstrated access to over 25 Tyr-linked cyclic peptides (3- to 11-residue cycles) with good tolerance of native residue side chain functionalities. Importantly, this method is simple to perform, and product formation can be quickly confirmed by mass spectrometric and 1H NMR spectroscopic analyses.
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Affiliation(s)
- E Dalles Keyes
- Department of Chemistry, University of Utah, Salt Lake City, UT, United States
| | - Marcus C Mifflin
- Department of Chemistry, University of Utah, Salt Lake City, UT, United States
| | - Maxwell J Austin
- Department of Chemistry, University of Utah, Salt Lake City, UT, United States
| | - Jesus Sandres
- Department of Chemistry, University of Utah, Salt Lake City, UT, United States
| | - Andrew G Roberts
- Department of Chemistry, University of Utah, Salt Lake City, UT, United States.
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2
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Kundu S, Maji MS. Solution-Phase Late-Stage Chemoselective Photocatalytic Removal of Sulfonyl and Phenacyl Groups in Peptides. Chemistry 2024; 30:e202400033. [PMID: 38345998 DOI: 10.1002/chem.202400033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Indexed: 03/07/2024]
Abstract
Herein, BPC catalyzed visible-light-triggered target-specific late-stage solution phase desulfonylation from tryptophan in oligopeptides is portrayed by overcoming the isolation issue up to octamers. This robust and mild method is highly predictable and chemoselective, tolerating myriad of functional groups in aza-heteroaromatics and peptides. Interestingly, reductive desulfonylation is also amenable to biologically significant reactive histidine and tyrosine side chains, signifying the versatility of the strategy. Additional efficacy of BPC is demonstrated by solution phase phenacyl deprotection from C-terminal in peptides. Furthermore, excellent catalyst loading of 0.5 mol% and recyclability demonstrate the practical utility and applicability of this strategy.
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Affiliation(s)
- Samrat Kundu
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India
| | - Modhu Sudan Maji
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India
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3
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Carson MC, Kozlowski MC. Recent advances in oxidative phenol coupling for the total synthesis of natural products. Nat Prod Rep 2024; 41:208-227. [PMID: 37294301 PMCID: PMC10709532 DOI: 10.1039/d3np00009e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Covering: 2008 to 2023This review will describe oxidative phenol coupling as applied in the total synthesis of natural products. This review covers catalytic and electrochemical methods with a brief comparison to stoichiometric and enzymatic systems assessing their practicality, atom economy, and other measures. Natural products forged by C-C and C-O oxidative phenol couplings as well as from alkenyl phenol couplings will be addressed. Additionally, exploration into catalytic oxidative coupling of phenols and other related species (carbazoles, indoles, aryl ethers, etc.) will be surveyed. Future directions of this particular area of research will also be assessed.
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Affiliation(s)
- Matthew C Carson
- Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
| | - Marisa C Kozlowski
- Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
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4
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Tang J, Lu F, Geng Y, Liu Y, Zhang E. Site-Selective Modification of Peptides via Late-Stage Pd-Catalyzed Tandem Reaction of Phenylalanine with Benzoquinone. Org Lett 2023; 25:5378-5382. [PMID: 37439546 DOI: 10.1021/acs.orglett.3c01952] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
An efficient and straightforward approach for site-selective functionalization of phenylalanine and phenylalanine-containing peptide via a Pd-catalyzed tandem reaction has been developed. The robust method underwent dual C-H activation, including C-C coupling with benzoquinone and intramolecular C-N cyclization, providing a feasible and rapid synthetic route to incorporate 4-benzoquinone-indoline fragments into peptides.
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Affiliation(s)
- Jian Tang
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Fengjie Lu
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Yujie Geng
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Yanxia Liu
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Ensheng Zhang
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
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5
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Keyes ED, Mifflin MC, Austin MJ, Alvey BJ, Lovely LH, Smith A, Rose TE, Buck-Koehntop BA, Motwani J, Roberts AG. Chemoselective, Oxidation-Induced Macrocyclization of Tyrosine-Containing Peptides. J Am Chem Soc 2023; 145:10071-10081. [PMID: 37119237 DOI: 10.1021/jacs.3c00210] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Inspired by nature's wide range of oxidation-induced modifications to install cross-links and cycles at tyrosine (Tyr) and other phenol-containing residue side chains, we report a Tyr-selective strategy for the preparation of Tyr-linked cyclic peptides. This approach leverages N4-substituted 1,2,4-triazoline-3,5-diones (TADs) as azo electrophiles that react chemoselectively with the phenolic side chain of Tyr residues to form stable C-N1-linked cyclic peptides. In the developed method, a precursor 1,2,4-triazolidine-3,5-dione moiety, also known as urazole, is readily constructed at any free amine revealed on a solid-supported peptide. Once prepared, the N4-substituted urazole peptide is selectively oxidized using mild, peptide-compatible conditions to generate an electrophilic N4-substituted TAD peptide intermediate that reacts selectively under aqueous conditions with internal and terminal Tyr residues to furnish Tyr-linked cyclic peptides. The approach demonstrates good tolerance of native residue side chains and enables access to cyclic peptides ranging from 3- to 11-residues in size (16- to 38-atom-containing cycles). The identity of the installed Tyr-linkage, a stable covalent C-N1 bond, was characterized using NMR spectroscopy. Finally, we applied the developed method to prepare biologically active Tyr-linked cyclic peptides bearing the integrin-binding RGDf epitope.
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Affiliation(s)
- E Dalles Keyes
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Marcus C Mifflin
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Maxwell J Austin
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Brighton J Alvey
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Lotfa H Lovely
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Andriea Smith
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Tristin E Rose
- 1200 Pharma LLC, 6100 Bristol Parkway, Culver City, California 90230, United States
| | - Bethany A Buck-Koehntop
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Jyoti Motwani
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Andrew G Roberts
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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6
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Cai C, Wang F, Xiao X, Sheng W, Liu S, Chen J, Zheng J, Xie R, Bai Z, Wang H. Macrocyclization of bioactive peptides with internal thiazole motifs via palladium-catalyzed C-H olefination. Chem Commun (Camb) 2022; 58:4861-4864. [PMID: 35348132 DOI: 10.1039/d1cc06764h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Peptides containing thiazole fragments represent a large group of bioactive compounds with potential medicinal applications. However, methods for efficient synthesis of these compounds with structural diversity are limited. Herein, we report a method for modification and macrocyclization of thiazole-containing peptides through palladium-catalyzed δ-C(sp2)-H olefination. In this protocol, the thiazole and neighboring amide bonds act as directing groups, which allows site-specific olefination of phenylalanine, tryptophan and tyrosine residues. This chemistry exhibits broad substrate scope and provides facile access to peptide-peptide conjugates and peptide macrocycles. Our results highlight the potency and applicability of thiazole motifs in promoting Pd-catalyzed functionalization of peptides.
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Affiliation(s)
- Chuangxu Cai
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Feifei Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Xiuyun Xiao
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Wangjian Sheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Shu Liu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Jun Chen
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Jie Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Ran Xie
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Zengbing Bai
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Huan Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
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7
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Ibara M, Abe T, Sawada D. Chemo- and Site-Selective Replacement of N-Terminal Carbamates in Peptides. Org Lett 2022; 24:2131-2136. [PMID: 35285651 DOI: 10.1021/acs.orglett.2c00370] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In peptide synthesis, it is important to distinguish the terminal amino group and carry out the selective transformation of only the N-terminal protecting group. We describe herein a reaction for the chemo- and site-selective replacement of carbamates with various other carbamates only at the N-terminus of peptides. We demonstrate the scope of carbamates and peptides and the introduction of fluorine into a peptide. This strategy is applicable to the late stage of peptide synthesis.
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Affiliation(s)
- Miho Ibara
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 7008530, Japan
| | - Takumi Abe
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 7008530, Japan
| | - Daisuke Sawada
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 7008530, Japan
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8
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Allouche EMD, Grinhagena E, Waser J. Hypervalent Iodine-Mediated Late-Stage Peptide and Protein Functionalization. Angew Chem Int Ed Engl 2022; 61:e202112287. [PMID: 34674359 PMCID: PMC9299824 DOI: 10.1002/anie.202112287] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Indexed: 12/20/2022]
Abstract
Hypervalent iodine compounds are powerful reagents for the development of novel transformations. As they exhibit low toxicity, high functional group tolerance, and stability in biocompatible media, they have been used for the functionalization of biomolecules. Herein, we report recent advances up to June 2021 in peptide and protein modification using hypervalent iodine reagents. Their use as group transfer or oxidizing reagents is discussed in this Minireview, including methods targeting polar, aromatic, or aliphatic amino acids and peptide termini.
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Affiliation(s)
- Emmanuelle M. D. Allouche
- Laboratory of Catalysis and Organic SynthesisInstitute of Chemical Sciences and EngineeringEcole Polytechnique Fédérale de Lausanne, EPFL, SB ISIC, LCSO, BCH 14021015LausanneSwitzerland
| | - Elija Grinhagena
- Laboratory of Catalysis and Organic SynthesisInstitute of Chemical Sciences and EngineeringEcole Polytechnique Fédérale de Lausanne, EPFL, SB ISIC, LCSO, BCH 14021015LausanneSwitzerland
| | - Jerome Waser
- Laboratory of Catalysis and Organic SynthesisInstitute of Chemical Sciences and EngineeringEcole Polytechnique Fédérale de Lausanne, EPFL, SB ISIC, LCSO, BCH 14021015LausanneSwitzerland
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9
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Allouche EMD, Grinhagena E, Waser J. Hypervalent Iodine‐Mediated Late‐Stage Peptide and Protein Functionalization. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Emmanuelle M. D. Allouche
- Laboratory of Catalysis and Organic Synthesis Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne, EPFL, SB ISIC, LCSO, BCH 1402 1015 Lausanne Switzerland
| | - Elija Grinhagena
- Laboratory of Catalysis and Organic Synthesis Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne, EPFL, SB ISIC, LCSO, BCH 1402 1015 Lausanne Switzerland
| | - Jerome Waser
- Laboratory of Catalysis and Organic Synthesis Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne, EPFL, SB ISIC, LCSO, BCH 1402 1015 Lausanne Switzerland
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10
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Swain JA, Walker SR, Calvert MB, Brimble MA. The tryptophan connection: cyclic peptide natural products linked via the tryptophan side chain. Nat Prod Rep 2021; 39:410-443. [PMID: 34581375 DOI: 10.1039/d1np00043h] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Covering: from 1938 up to March 2021The electron-rich indole side chain of tryptophan is a versatile substrate for peptide modification. Upon the action of various cyclases, the tryptophan side chain may be linked to a nearby amino acid residue, opening the door to a diverse range of cyclic peptide natural products. These compounds exhibit a wide array of biological activity and possess fascinating molecular architectures, which have made them popular targets for total synthesis studies. This review examines the isolation and bioactivity of tryptophan-linked cyclic peptide natural products, along with a discussion of their first total synthesis, and biosynthesis where this has been studied.
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Affiliation(s)
- Jonathan A Swain
- School of Chemical Sciences, The University of Auckland, Symonds Street, Auckland 1010, New Zealand.
| | - Stephen R Walker
- School of Chemical Sciences, The University of Auckland, Symonds Street, Auckland 1010, New Zealand.
| | - Matthew B Calvert
- School of Chemical Sciences, The University of Auckland, Symonds Street, Auckland 1010, New Zealand.
| | - Margaret A Brimble
- School of Chemical Sciences, The University of Auckland, Symonds Street, Auckland 1010, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Symonds Street, Auckland 1010, New Zealand
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11
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Brandhofer T, Stinglhamer M, Derdau V, Méndez M, Pöverlein C, García Mancheño O. Easy access to drug building-blocks through benzylic C-H functionalization of phenolic ethers by photoredox catalysis. Chem Commun (Camb) 2021; 57:6756-6759. [PMID: 34132710 DOI: 10.1039/d1cc01756j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A visible light-mediated photocatalyzed C-C-bond forming method for the benzylic C-H functionalization of phenolether containing synthetic building blocks based on a radical-cation/deprotonation strategy is reported. This method allows the mild, selective generation of benzyl radicals in phenolic complex molecules and drug-like compounds, providing new entries in synthetic and medicinal chemistry.
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Affiliation(s)
- Tobias Brandhofer
- Organic Chemistry Institute, Westfälische-Wilhelms University Münster, Correnstraße 36, Münster 48149, UK.
| | - Martin Stinglhamer
- Organic Chemistry Institute, Westfälische-Wilhelms University Münster, Correnstraße 36, Münster 48149, UK.
| | - Volker Derdau
- Sanofi-Aventis Deutschland GmbH, R&D Integrated Drug Discovery, Industriepark Höchst, Frankfurt am Main D-65926, UK
| | - María Méndez
- Sanofi-Aventis Deutschland GmbH, R&D Integrated Drug Discovery, Industriepark Höchst, Frankfurt am Main D-65926, UK
| | - Christoph Pöverlein
- Sanofi-Aventis Deutschland GmbH, R&D Integrated Drug Discovery, Industriepark Höchst, Frankfurt am Main D-65926, UK
| | - Olga García Mancheño
- Organic Chemistry Institute, Westfälische-Wilhelms University Münster, Correnstraße 36, Münster 48149, UK.
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12
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Correa A. Metal‐Catalyzed C(sp
2
)−H Functionalization Processes of Phenylalanine‐ and Tyrosine‐Containing Peptides. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100374] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Arkaitz Correa
- University of the Basque Country (UPV/EHU) Department of Organic Chemistry I Joxe Mari Korta R&D Center Avda. Tolosa 72 20018 Donostia-San Sebastián Spain
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13
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Lázaro-Milla C, Yanai H, Almendros P. Metal-Free C-C/C-N/C-C Bond Formation Cascade for the Synthesis of (Trifluoromethyl)sulfonylated Cyclopenta[ b]indolines. Org Lett 2021; 23:2921-2926. [PMID: 33793251 PMCID: PMC8479863 DOI: 10.1021/acs.orglett.1c00557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Indexed: 11/29/2022]
Abstract
A bis(triflyl)ethylation [triflyl = (trifluoromethyl)sulfonyl] inserted into a sequential cyclization cascade resulted in the direct formation of gem-bis(triflyl)ated cyclopenta[b]indolines from anilide-derived allenols and alkenols. This catalyst- and irradiation-free sequence facilitated the efficient preparation of functionalized tricyclic indoline cores bearing two contiguous stereocenters. The formed cyclopenta[b]indolines can be easily transformed into a wide variety of triflylated indolines, including the tetracycle ring system found in polyveoline.
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Affiliation(s)
- Carlos Lázaro-Milla
- Grupo
de Lactamas y Heterociclos Bioactivos, Departamento de Química
Orgánica, Unidad Asociada al CSIC, Facultad de Química, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Hikaru Yanai
- School
of Pharmacy, Tokyo University of Pharmacy
and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Pedro Almendros
- Instituto
de Química Orgánica General, IQOG, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
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