1
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Hu N, Sun S, Wang X, Li S. Modular Synthesis and Antimicrobial Investigation of Mycoleptodiscin A and Simplified Indolosesquiterpenoids. Org Lett 2024. [PMID: 38958211 DOI: 10.1021/acs.orglett.4c01932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
The structure-activity relationship of the unusual indolosesquiterpenoid mycoleptodiscin A is unknown due to natural scarcity and inefficient synthesis. A modular approach leveraging Larock indole synthesis has been established to access mycoleptodiscin A and a divergent collection of drimenyl indoles. It features the utilization of an inexpensive (+)-sclareolide, modularity, purification-economy, and scalability, which facilitates the first biological evaluation of mycoleptodiscin A and related precursors.
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Affiliation(s)
- Nvdan Hu
- State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang 550025, China
- College of Food and Pharmaceutical Engineering, Guizhou Institute of Technology, Guiyang, Guizhou 550003, China
| | - Shengxin Sun
- State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang 550025, China
| | - Xia Wang
- State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang 550025, China
| | - Shengkun Li
- State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang 550025, China
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2
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Yu L, Nagata Y, Nakamura H. Atroposelective Total Synthesis of Cihunamide B. J Am Chem Soc 2024; 146:2549-2555. [PMID: 38240691 DOI: 10.1021/jacs.3c11016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
A short, atroposelective synthesis of cihunamide B (1) is reported. The feature of this report is the decagram-scale SNAr reaction of l-tryptophan derivatives, followed by atroposelective Larock macrocyclization. This strategy allowed the construction of a Trp-Trp cross-linkage with unprecedented atropisomerism. The atroposelectivity of this Larock macrocyclization has been investigated through a combination of experimental and computational chemistry, yielding detailed insights into the synthesis of biaryl linkages. It also enabled the concise synthesis of cihunamide B (1), which is expected to be a potential antibacterial agent.
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Affiliation(s)
- Longhui Yu
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong 999077, China
| | - Yuuya Nagata
- WPI Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
| | - Hugh Nakamura
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong 999077, China
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3
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Walker KL, Loach RP, Movassaghi M. Total synthesis of complex 2,5-diketopiperazine alkaloids. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2023; 90:159-206. [PMID: 37716796 PMCID: PMC10955524 DOI: 10.1016/bs.alkal.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/18/2023]
Abstract
The 2,5-diketopiperazine (DKP) motif is present in many biologically relevant, complex natural products. The cyclodipeptide substructure offers structural rigidity and stability to proteolysis that makes these compounds promising candidates for medical applications. Due to their fascinating molecular architecture, synthetic organic chemists have focused significant effort on the total synthesis of these compounds. This review covers many such efforts on the total synthesis of DKP containing complex alkaloid natural products.
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Affiliation(s)
- Katherine L Walker
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Richard P Loach
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Mohammad Movassaghi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, United States.
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4
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Singer RA, Monfette S, Bernhardson D, Tcyrulnikov S, Hubbell AK, Hansen EC. Recent Advances in Nonprecious Metal Catalysis. Org Process Res Dev 2022. [DOI: 10.1021/acs.oprd.2c00310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Robert A. Singer
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Sebastien Monfette
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - David Bernhardson
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Sergei Tcyrulnikov
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Aran K. Hubbell
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Eric C. Hansen
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
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5
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Kelly SP, Shende VV, Flynn AR, Dan Q, Ye Y, Smith JL, Tsukamoto S, Sigman MS, Sherman DH. Data Science-Driven Analysis of Substrate-Permissive Diketopiperazine Reverse Prenyltransferase NotF: Applications in Protein Engineering and Cascade Biocatalytic Synthesis of (-)-Eurotiumin A. J Am Chem Soc 2022; 144:19326-19336. [PMID: 36223664 PMCID: PMC9831672 DOI: 10.1021/jacs.2c06631] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Prenyltransfer is an early-stage carbon-hydrogen bond (C-H) functionalization prevalent in the biosynthesis of a diverse array of biologically active bacterial, fungal, plant, and metazoan diketopiperazine (DKP) alkaloids. Toward the development of a unified strategy for biocatalytic construction of prenylated DKP indole alkaloids, we sought to identify and characterize a substrate-permissive C2 reverse prenyltransferase (PT). As the first tailoring event within the biosynthesis of cytotoxic notoamide metabolites, PT NotF catalyzes C2 reverse prenyltransfer of brevianamide F. Solving a crystal structure of NotF (in complex with native substrate and prenyl donor mimic dimethylallyl S-thiolodiphosphate (DMSPP)) revealed a large, solvent-exposed active site, intimating NotF may possess a significantly broad substrate scope. To assess the substrate selectivity of NotF, we synthesized a panel of 30 sterically and electronically differentiated tryptophanyl DKPs, the majority of which were selectively prenylated by NotF in synthetically useful conversions (2 to >99%). Quantitative representation of this substrate library and development of a descriptive statistical model provided insight into the molecular origins of NotF's substrate promiscuity. This approach enabled the identification of key substrate descriptors (electrophilicity, size, and flexibility) that govern the rate of NotF-catalyzed prenyltransfer, and the development of an "induced fit docking (IFD)-guided" engineering strategy for improved turnover of our largest substrates. We further demonstrated the utility of NotF in tandem with oxidative cyclization using flavin monooxygenase, BvnB. This one-pot, in vitro biocatalytic cascade enabled the first chemoenzymatic synthesis of the marine fungal natural product, (-)-eurotiumin A, in three steps and 60% overall yield.
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Affiliation(s)
- Samantha P. Kelly
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA.,These authors contributed equally: Samantha P. Kelly, Vikram V. Shende
| | - Vikram V. Shende
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA.,These authors contributed equally: Samantha P. Kelly, Vikram V. Shende
| | - Autumn R. Flynn
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Qingyun Dan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ying Ye
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Janet L. Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sachiko Tsukamoto
- Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan
| | - Matthew S. Sigman
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
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6
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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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7
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Nesic M, Ryffel DB, Maturano J, Shevlin M, Pollack SR, Gauthier DR, Trigo-Mouriño P, Zhang LK, Schultz DM, McCabe Dunn JM, Campeau LC, Patel NR, Petrone DA, Sarlah D. Total Synthesis of Darobactin A. J Am Chem Soc 2022; 144:14026-14030. [PMID: 35900216 DOI: 10.1021/jacs.2c05891] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The collaborative total synthesis of darobactin A, a recently isolated antibiotic that selectively targets Gram-negative bacteria, has been accomplished in a convergent fashion with a longest linear sequence of 16 steps from d-Garner's aldehyde and l-serine. Scalable routes toward three non-canonical amino acids were developed to enable the synthesis. The closure of the bismacrocycle was realized through sequential, halogen-selective Larock indole syntheses, where the proper order of cyclizations proved crucial for the formation of the desired atropisomer of the natural product.
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Affiliation(s)
- Marko Nesic
- Department of Chemistry and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - David B Ryffel
- Department of Chemistry and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jonathan Maturano
- Department of Chemistry and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Michael Shevlin
- Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - Scott R Pollack
- Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - Donald R Gauthier
- Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - Pablo Trigo-Mouriño
- Analytical Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Li-Kang Zhang
- Analytical Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Danielle M Schultz
- Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - Jamie M McCabe Dunn
- Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - Louis-Charles Campeau
- Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - Niki R Patel
- Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - David A Petrone
- Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - David Sarlah
- Department of Chemistry and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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8
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García-Domínguez P, Areal A, Alvarez R, de Lera AR. Chemical synthesis in competition with global genome mining and heterologous expression for the preparation of dimeric tryptophan-derived 2,5-dioxopiperazines. Nat Prod Rep 2022; 39:1172-1225. [PMID: 35470828 DOI: 10.1039/d2np00006g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Covering: up to the end of 2021Within the 2,5-dioxopiperazines-containing natural products, those generated from tryptophan allow further structural diversification due to the rich chemical reactivity of the indole heterocycle. The great variety of natural products, ranging from simple dimeric bispyrrolidinoindoline dioxopiperazines and tryptophan-derived dioxopiperazine/pyrrolidinoindoline dioxopiperazine analogs to complex polycyclic downstream metabolites containing transannular connections between the subunits, will be covered. These natural products are constructed by Nature using hybrid polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) assembly lines. Mining of microbial genome sequences has more recently allowed the study of the metabolic routes and the discovery of their hidden biosynthetic potential. The competition (ideally, also the combined efforts) between their isolation from the cultures of the producing microorganisms after global genome mining and heterologous expression and the synthetic campaigns, has more recently allowed the successful generation and structural confirmation of these natural products. Their biological activities as well as their proposed biogenetic routes and computational studies on biogenesis will also be covered.
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Affiliation(s)
| | - Andrea Areal
- CINBIO and Universidade de Vigo, 36310 Vigo, Spain.
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9
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Yiamsawat K, Gable KP, Chuawong P. Dissecting the Electronic Contribution to the Regioselectivity of the Larock Heteroannulation Reaction in the Oxidative Addition and Carbopalladation Steps. J Org Chem 2022; 87:1218-1229. [PMID: 34989564 DOI: 10.1021/acs.joc.1c02560] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Substituted 2-iodoaniline derivatives were prepared and utilized as reactants, along with asymmetric diarylacetylenes, to synthesize a series of 6-substituted-2,3-diarylindole derivatives via the Larock heteroannulation reaction. Electron-donating substituents on the 2-iodoaniline derivatives retarded the reaction, while electron-withdrawing substituents provided a complete conversion to the indole products. In addition, the electronic properties of the substituted 2-iodoaniline reactants displayed no influence toward regioselectivity. On the contrary, the electronic effect from unsymmetrical diarylacetylenes significantly influenced the regiochemical outcome of the reaction. Density functional theory calculations of the oxidative addition and carbopalladation steps revealed the electronic influences of the substituted 2-iodoaniline derivatives toward the overall rate of the reaction. In contrast, the electronic properties of the asymmetric diarylacetylene remained the critical product-determining factor of regioselectivity.
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Affiliation(s)
- Kanyapat Yiamsawat
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Special Research Unit for Advanced Magnetic Resonance (AMR), Kasetsart University, Bangkok 10900, Thailand
| | - Kevin P Gable
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
| | - Pitak Chuawong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Special Research Unit for Advanced Magnetic Resonance (AMR), Kasetsart University, Bangkok 10900, Thailand
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10
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Yan X, Liu CF, An XT, Ge XM, Zhang Q, Pang LH, Bao X, Fan CA. Copper-Catalyzed (4+1) Cascade Annulation of Terminal Alkynes with 2-(Tosylmethyl)anilines: Synthesis of 2,3-Disubstituted Indoles. Org Lett 2021; 23:8905-8909. [PMID: 34756037 DOI: 10.1021/acs.orglett.1c03402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A novel strategy based on Cu-catalyzed (4+1) cascade annulation of terminal alkynes as one-carbon synthons with 2-(tosylmethyl)anilines has been developed for the expeditious synthesis of 2,3-disubstituted indoles, in which in situ generations of aza-o-quinone methides and alkynyl-copper(I) species are involved. This annulation provides an effective method for the assembly of synthetically and structurally interesting 2,3-disubstituted indoles.
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Affiliation(s)
- Xu Yan
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
| | - Chun-Fang Liu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
| | - Xian-Tao An
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
| | - Xiao-Min Ge
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
| | - Qing Zhang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
| | - Lin-Han Pang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
| | - Xu Bao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
| | - Chun-An Fan
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China
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11
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Heravi MM, Amiri Z, Kafshdarzadeh K, Zadsirjan V. Synthesis of indole derivatives as prevalent moieties present in selected alkaloids. RSC Adv 2021; 11:33540-33612. [PMID: 35497516 PMCID: PMC9042329 DOI: 10.1039/d1ra05972f] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/10/2021] [Indexed: 02/02/2023] Open
Abstract
Indoles are a significant heterocyclic system in natural products and drugs. They are important types of molecules and natural products and play a main role in cell biology. The application of indole derivatives as biologically active compounds for the treatment of cancer cells, microbes, and different types of disorders in the human body has attracted increasing attention in recent years. Indoles, both natural and synthetic, show various biologically vital properties. Owing to the importance of this significant ring system, the investigation of novel methods of synthesis have attracted the attention of the chemical community. In this review, we aim to highlight the construction of indoles as a moiety in selected alkaloids.
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Affiliation(s)
- Majid M Heravi
- Department of Chemistry, School of Physics and Chemistry, Alzahra University Vanak Tehran Iran +98 2188041344 +98 9121329147
| | - Zahra Amiri
- Department of Chemistry, School of Physics and Chemistry, Alzahra University Vanak Tehran Iran +98 2188041344 +98 9121329147
| | - Kosar Kafshdarzadeh
- Department of Chemistry, School of Physics and Chemistry, Alzahra University Vanak Tehran Iran +98 2188041344 +98 9121329147
| | - Vahideh Zadsirjan
- Department of Chemistry, School of Physics and Chemistry, Alzahra University Vanak Tehran Iran +98 2188041344 +98 9121329147
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12
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Ganley JM, Murray PRD, Knowles RR. Photocatalytic Generation of Aminium Radical Cations for C─N Bond Formation. ACS Catal 2020; 10:11712-11738. [PMID: 33163257 PMCID: PMC7644096 DOI: 10.1021/acscatal.0c03567] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Aminium radical cations have been extensively studied as electrophilic aminating species that readily participate in C─N bond forming processes with alkenes and arenes. However, their utility in synthesis has been limited, as their generation required unstable, reactive starting materials and harsh reaction conditions. Visible-light photoredox catalysis has emerged as a platform for the mild production of aminium radical cations from either unfunctionalized or N-functionalized amines. This Perspective covers recent synthetic methods that rely on the photocatalytic generation of aminium radical cations for C─N bond formation, specifically in the context of alkene hydroamination, arene C─H bond amination, and the mesolytic bond cleavage of alkoxyamines.
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Affiliation(s)
- Jacob M Ganley
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Philip R D Murray
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Robert R Knowles
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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13
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Shende VV, Khatri Y, Newmister SA, Sanders JN, Lindovska P, Yu F, Doyon TJ, Kim J, Houk KN, Movassaghi M, Sherman DH. Structure and Function of NzeB, a Versatile C-C and C-N Bond-Forming Diketopiperazine Dimerase. J Am Chem Soc 2020; 142:17413-17424. [PMID: 32786740 DOI: 10.1021/jacs.0c06312] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dimeric diketopiperazine (DKPs) alkaloids are a diverse family of natural products (NPs) whose unique structural architectures and biological activities have inspired the development of new synthetic methodologies to access these molecules. However, catalyst-controlled methods that enable the selective formation of constitutional and stereoisomeric dimers from a single monomer are lacking. To resolve this long-standing synthetic challenge, we sought to characterize the biosynthetic enzymes that assemble these NPs for application in biocatalytic syntheses. Genome mining enabled identification of the cytochrome P450, NzeB (Streptomyces sp. NRRL F-5053), which catalyzes both intermolecular carbon-carbon (C-C) and carbon-nitrogen (C-N) bond formation. To identify the molecular basis for the flexible site-selectivity, stereoselectivity, and chemoselectivity of NzeB, we obtained high-resolution crystal structures (1.5 Å) of the protein in complex with native and non-native substrates. This, to our knowledge, represents the first crystal structure of an oxidase catalyzing direct, intermolecular C-H amination. Site-directed mutagenesis was utilized to assess the role individual active-site residues play in guiding selective DKP dimerization. Finally, computational approaches were employed to evaluate plausible mechanisms regarding NzeB function and its ability to catalyze both C-C and C-N bond formation. These results provide a structural and computational rationale for the catalytic versatility of NzeB, as well as new insights into variables that control selectivity of CYP450 diketopiperazine dimerases.
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Affiliation(s)
| | | | | | - Jacob N Sanders
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Petra Lindovska
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | | | | | - Justin Kim
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Mohammad Movassaghi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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14
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Mari G, De Crescentini L, Favi G, Santeusanio S, Mantellini F. Metal and Oxidant Free Construction of Substituted‐ and/or Polycyclic Indoles: A Useful Alternative to Bischler and Related Syntheses. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Giacomo Mari
- Department of Biomolecular Sciences University of Urbino “Carlo Bo” Via I Maggetti 24 61029 Urbino (PU) Italy
| | - Lucia De Crescentini
- Department of Biomolecular Sciences University of Urbino “Carlo Bo” Via I Maggetti 24 61029 Urbino (PU) Italy
| | - Gianfranco Favi
- Department of Biomolecular Sciences University of Urbino “Carlo Bo” Via I Maggetti 24 61029 Urbino (PU) Italy
| | - Stefania Santeusanio
- Department of Biomolecular Sciences University of Urbino “Carlo Bo” Via I Maggetti 24 61029 Urbino (PU) Italy
| | - Fabio Mantellini
- Department of Biomolecular Sciences University of Urbino “Carlo Bo” Via I Maggetti 24 61029 Urbino (PU) Italy
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15
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General synthesis of unnatural 4-, 5-, 6-, and 7-bromo-d-tryptophans by means of a regioselective indole alkylation. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.151923] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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16
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Peng H, Jiang K, Zhen G, Wang F, Yin B. Access to N-unprotected 2-amide-substituted indoles from Ugi adducts via palladium-catalyzed intramolecular cyclization of o-iodoanilines bearing furan rings. RSC Adv 2020; 10:11750-11754. [PMID: 35496608 PMCID: PMC9050509 DOI: 10.1039/d0ra01830a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 02/28/2020] [Indexed: 11/21/2022] Open
Abstract
A variety of N-unprotected 2-amide-substituted indoles were synthesized from readily available furfural-based Ugi adducts in moderate to good yields via palladium-catalyzed intramolecular cyclization of o-iodoanilines bearing furan rings. These reactions involved a cascade sequence consisting of dearomatizing arylation, opening of the furan ring, and deprotection of the N atom. A variety of N-unprotected 2-amide-substituted indoles were synthesized from readily available furfural-based Ugi adducts in moderate to good yields via palladium-catalyzed intramolecular cyclization of o-iodoanilines bearing furan rings.![]()
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Affiliation(s)
- Hui Peng
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
| | - Kai Jiang
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
| | - Guangjin Zhen
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
| | - Furong Wang
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
| | - Biaolin Yin
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
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17
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Isley NA, Endo Y, Wu ZC, Covington BC, Bushin LB, Seyedsayamdost MR, Boger DL. Total Synthesis and Stereochemical Assignment of Streptide. J Am Chem Soc 2019; 141:17361-17369. [PMID: 31577142 DOI: 10.1021/jacs.9b09067] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Streptide (1) is a peptide-derived macrocyclic natural product that has attracted considerable attention since its discovery in 2015. It contains an unprecedented post-translational modification that intramolecularly links the β-carbon (C3) of a residue 2 lysine with the C7 of a residue 6 tryptophan, thereby forming a 20-membered cyclic peptide. Herein, we report the first total synthesis of streptide that confirms the regiochemistry of the lysine-tryptophan cross-link and provides an unambiguous assignment of the stereochemistry (3R vs 3S) of the lysine-2 C3 center. Both the 3R and the originally assigned 3S lysine diastereomers were independently prepared by total synthesis, and it is the former, not the latter, that was found to correlate with the natural product. The approach enlists a powerful Pd(0)-mediated indole annulation for the key macrocyclization of the complex core peptide, utilizes an underdeveloped class of hypervalent iodine(III) aryl substrates in a palladium-catalyzed C-H activation/β-arylation reaction conducted on a lysine derivative, and provides access to material with which the role of streptide and related natural products may be examined.
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Affiliation(s)
- Nicholas A Isley
- Department of Chemistry and Skaggs Institute for Chemical Biology , The Scripps Research Institute , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Yusuke Endo
- Department of Chemistry and Skaggs Institute for Chemical Biology , The Scripps Research Institute , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Zhi-Chen Wu
- Department of Chemistry and Skaggs Institute for Chemical Biology , The Scripps Research Institute , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
| | - Brett C Covington
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Leah B Bushin
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | | | - Dale L Boger
- Department of Chemistry and Skaggs Institute for Chemical Biology , The Scripps Research Institute , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States
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18
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Li X, Deng X, Coyne AG, Srinivasan R. meta-Nitration of Arenes Bearing ortho/para Directing Group(s) Using C-H Borylation. Chemistry 2019; 25:8018-8023. [PMID: 30974007 DOI: 10.1002/chem.201901633] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Indexed: 11/07/2022]
Abstract
Herein, we report the meta-nitration of arenes bearing ortho/para directing group(s) using the iridium-catalyzed C-H borylation reaction followed by a newly developed copper(II)-catalyzed transformation of the crude aryl pinacol boronate esters into the corresponding nitroarenes in a one-pot fashion. This protocol allows the synthesis of meta-nitrated arenes that are tedious to prepare or require multistep synthesis using the existing methods. The reaction tolerates a wide array of ortho/para-directing groups, such as -F, -Cl, -Br, -CH3 , -Et, -iPr -OCH3 , and -OCF3 . It also provides regioselective access to the nitro derivatives of π-electron-deficient heterocycles, such as pyridine and quinoline derivatives. The application of this method is demonstrated in the late-stage modification of complex molecules and also in the gram-scale preparation of an intermediate en route to the FDA-approved drug Nilotinib. Finally, we have shown that the nitro product obtained by this strategy can also be directly converted to the aniline or hindered amine through Baran's amination protocol.
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Affiliation(s)
- Xuejing Li
- School of Pharmaceutical Science and Technology (SPST), Tianjin University, 92 Weijin Road, Building 24, Nankai District, Tianjin, 300072, P.R. China
| | - Xingwang Deng
- School of Pharmaceutical Science and Technology (SPST), Tianjin University, 92 Weijin Road, Building 24, Nankai District, Tianjin, 300072, P.R. China
| | - Anthony G Coyne
- University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Rajavel Srinivasan
- School of Pharmaceutical Science and Technology (SPST), Tianjin University, 92 Weijin Road, Building 24, Nankai District, Tianjin, 300072, P.R. China
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19
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Ali R, Ahamad MZ, Singh S, Haq W. Regioselective Synthesis of Symmetrical and Unsymmetrical Bis(heteroaryl)methane (BHM)-Containing Amino Acids. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Rafat Ali
- Medicinal and Process Chemistry Division; CSIR-Central Drug Research Institute; -226031 Lucknow India
| | - Mohd. Zisan Ahamad
- Medicinal and Process Chemistry Division; CSIR-Central Drug Research Institute; -226031 Lucknow India
| | - Shalini Singh
- Medicinal and Process Chemistry Division; CSIR-Central Drug Research Institute; -226031 Lucknow India
| | - Wahajul Haq
- Medicinal and Process Chemistry Division; CSIR-Central Drug Research Institute; -226031 Lucknow India
- Academy of Scientific and Innovative Research; -11000 New Delhi India
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20
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Dong Z, Zhang XW, Li W, Li ZM, Wang WY, Zhang Y, Liu W, Liu WB. Synthesis of N-Fused Polycyclic Indoles via Ligand-Free Palladium-Catalyzed Annulation/Acyl Migration Reaction. Org Lett 2019; 21:1082-1086. [DOI: 10.1021/acs.orglett.8b04128] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhan Dong
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Xiao-Wen Zhang
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Weishuang Li
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Zi-Meng Li
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Wen-Yan Wang
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Yan Zhang
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Wei Liu
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Wen-Bo Liu
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
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21
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Abstract
Indole is the most frequently found heterocyclic core structures in pharmaceuticals, natural products, agrochemicals, dyes and fragrances. For about 150 years, chemists were absorbed in finding new and easier synthetic strategies to build this nucleus. Many books and reviews have been written, but the number of new syntheses that appear in the literature, make necessary continuous updates. This reviews aims to give a comprehensive overview on indole synthesis catalyzed by transition metals appeared in the literature in the years 2016 and 2017.
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22
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Wolfard J, Xu J, Zhang H, Chung CK. Synthesis of Chiral Tryptamines via a Regioselective Indole Alkylation. Org Lett 2018; 20:5431-5434. [PMID: 30130113 DOI: 10.1021/acs.orglett.8b02335] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A practical synthesis of chiral tryptamines from simple, unprotected indoles has been developed. Indole nucleophiles prepared with MeMgCl in the presence of CuCl reacted with chiral cyclic sulfamidates almost exclusively at the C3-position of indole to form a variety of α- and/or β-substituted chiral tryptamines in good yield with excellent regioselectivity. The utility of this simple alkylation process has been demonstrated with the practical synthesis of two biologically active targets, cipargamin and TIK-301, which were completed in three steps, starting from the corresponding indole starting materials.
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Affiliation(s)
- Jens Wolfard
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Jie Xu
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Haiming Zhang
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Cheol K Chung
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
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23
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Chalyavi F, Gilmartin PH, Schmitz AJ, Fennie MW, Tucker MJ. Synthesis of 5-Cyano-Tryptophan as a Two-Dimensional Infrared Spectroscopic Reporter of Structure. Angew Chem Int Ed Engl 2018; 57:7528-7532. [PMID: 29710418 PMCID: PMC6002807 DOI: 10.1002/anie.201803849] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Indexed: 12/20/2022]
Abstract
A concise synthesis of protected 5-cyano-l-tryptophan (Trp5CN ) has been developed for 2D IR spectroscopic investigations within either peptides or proteins. To assess the potential of differently substituted cyano-tryptophans, several model cyano-indole systems were characterized using IR spectroscopy. Upon assessment of their spectroscopic properties, Trp5CN was integrated into a model peptide sequence, Trp5CN -Gly-Phe4CN , to elucidate its structure. This peptide demonstrates the capability of this probe to capture structural information by 2D IR spectroscopy. The 2D IR spectrum of the peptide in water was simulated to reveal a unique spectral signature resulting from the presence of dipolar coupling. The coupling strength between cyano labels was determined to be 1.4 cm-1 by matching the slopes along the max contour for the simulated and experimental spectrum. Using transition dipole coupling, a distance between the two probes of 13 Å was calculated.
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Affiliation(s)
- Farzaneh Chalyavi
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV, 89557, USA
| | - Philip H Gilmartin
- Department of Chemistry, University of Scranton, 204 Monroe Ave., Scranton, PA, 18510, USA
| | - Andrew J Schmitz
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV, 89557, USA
| | - Michael W Fennie
- Department of Chemistry, University of Scranton, 204 Monroe Ave., Scranton, PA, 18510, USA
| | - Matthew J Tucker
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV, 89557, USA
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24
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Synthesis of 5-Cyano-Tryptophan as a Two-Dimensional Infrared Spectroscopic Reporter of Structure. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Gentry EC, Rono LJ, Hale ME, Matsuura R, Knowles RR. Enantioselective Synthesis of Pyrroloindolines via Noncovalent Stabilization of Indole Radical Cations and Applications to the Synthesis of Alkaloid Natural Products. J Am Chem Soc 2018; 140:3394-3402. [PMID: 29432006 PMCID: PMC5896747 DOI: 10.1021/jacs.7b13616] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
While interest in the synthetic chemistry of radical cations continues to grow, controlling enantioselectivity in the reactions of these intermediates remains a challenge. Based on recent insights into the oxidation of tryptophan in enzymatic systems, we report a photocatalytic method for the generation of indole radical cations as hydrogen-bonded adducts with chiral phosphate anions. These noncovalent open-shell complexes can be intercepted by the stable nitroxyl radical TEMPO· to form alkoxyamine-substituted pyrroloindolines with high levels of enantioselectivity. Further elaboration of these optically enriched adducts can be achieved via a catalytic single-electron oxidation/mesolytic cleavage sequence to furnish transient carbocation intermediates that may be intercepted by a wide range of nucleophiles. Taken together, this two-step sequence provides a simple catalytic method to access a wide range of substituted pyrroloindolines in enantioenriched form via a standard experimental protocol from a common synthetic intermediate. The design, development, mechanistic study, and scope of this process are presented, as are applications of this method to the synthesis of several dimeric pyrroloindoline natural products.
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Affiliation(s)
- Emily C. Gentry
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
| | - Lydia J. Rono
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
| | - Martina E. Hale
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
| | - Rei Matsuura
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
| | - Robert R. Knowles
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
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26
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Schotten C, Leist LGT, Semrau AL, Browne DL. A machine-assisted approach for the preparation of follow-on pharmaceutical compound libraries. REACT CHEM ENG 2018. [DOI: 10.1039/c8re00010g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Coupling of a continuous flow process to a robotic microwave device has led to a simple platform for the preparation of compound libraries, specifically the anti-migraine compound Zolmitriptan and several unknown analogues.
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Affiliation(s)
| | | | - A. Lisa Semrau
- School of Chemistry
- Cardiff University Main Building
- Cardiff
- UK
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27
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Krüll J, Hubert A, Nebel N, Prante O, Heinrich MR. Microwave‐Assisted Rapid One‐Pot Synthesis of Fused and Non‐Fused Indoles and 5‐[
18
F]Fluoroindoles from Phenylazocarboxylates. Chemistry 2017; 23:16174-16178. [DOI: 10.1002/chem.201703890] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Jasmin Krüll
- Department of Chemistry and Pharmacy, Pharmaceutical Chemistry Friedrich-Alexander Universität Erlangen-Nürnberg Schuhstraße 19 91052 Erlangen Germany
| | - Anja Hubert
- Department of Chemistry and Pharmacy, Pharmaceutical Chemistry Friedrich-Alexander Universität Erlangen-Nürnberg Schuhstraße 19 91052 Erlangen Germany
| | - Natascha Nebel
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry Friedrich-Alexander-Universität Erlangen-Nürnberg Schwabachanlage 6 91054 Erlangen Germany
| | - Olaf Prante
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry Friedrich-Alexander-Universität Erlangen-Nürnberg Schwabachanlage 6 91054 Erlangen Germany
| | - Markus R. Heinrich
- Department of Chemistry and Pharmacy, Pharmaceutical Chemistry Friedrich-Alexander Universität Erlangen-Nürnberg Schuhstraße 19 91052 Erlangen Germany
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28
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Indole-Indole Ullmann Cross-Coupling for CAr
-N Bond Formation: Total Synthesis of (-)-Aspergilazine A. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700842] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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29
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30
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Bober AE, Proto JT, Brummond KM. Intramolecular Didehydro-Diels–Alder Reaction for the Synthesis of Benzo- and Dihydrobenzo-Fused Heterocycles. Org Lett 2017; 19:1500-1503. [DOI: 10.1021/acs.orglett.7b00155] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ashley E. Bober
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Justin T. Proto
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Kay M. Brummond
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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