1
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Wootton JM, Tam JKF, Unsworth WP. Cascade ring expansion reactions for the synthesis of medium-sized rings and macrocycles. Chem Commun (Camb) 2024; 60:4999-5009. [PMID: 38655659 DOI: 10.1039/d4cc01303d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
This Feature Article discusses recent advances in the development of cascade ring expansion reactions for the synthesis of medium-sized rings and macrocycles. Cascade ring expansion reactions have much potential for use in the synthesis of biologically important medium-sized rings and macrocycles, most notably as they don't require high dilution conditions, which are commonly used in established end-to-end macrocyclisation methods. Operation by cascade ring expansion method can allow large ring products to be accessed via rearrangements that proceed exclusively by normal-sized ring cyclisation steps. Ensuring that there is adequate thermodynamic driving force for ring expansion is a key challenge when designing such methods, especially for the expansion of normal-sized rings into medium-sized rings. This Article is predominantly focused on methods developed in our own laboratory, with selected works by other groups also discussed. Thermodynamic considerations, mechanism, reaction design, route planning and future perspective for this field are all covered.
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Affiliation(s)
- Jack M Wootton
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Jerry K F Tam
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - William P Unsworth
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
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2
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Du L, Li X, Ding Y, Ma D, Yu C, Duan L. Design, Synthesis, and Bioactivities of N-Heterocyclic Ureas as Strigolactone Response Antagonists against Parasitic-Weed Seed Germination. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 38593208 DOI: 10.1021/acs.jafc.3c08174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
The pernicious parasitism exhibited by root parasitic weeds such as Orobanche and Striga poses substantial peril to agricultural productivity and global food security. This deleterious phenomenon hinges upon the targeted induction of the signaling molecule strigolactones (SLs). Consequently, the identification of prospective SL antagonists holds significant promise in the realm of mitigating the infection of these pernicious weeds. In this study, we synthesized and characterized D12 based on a potent SL antagonist KK094. In vivo assay results demonstrated that D12 remarkably impedes the germination of Phelipanche aegyptiaca and Striga asiatica seeds, while also alleviating the inhibitory consequence of the SL analogue GR24 on hypocotyl elongation in Arabidopsis thaliana. The docking study and ITC assay indicated that D12 can interact strongly with the SL receptor protein, which may interfere with the binding of SL to the receptor protein as a result. In addition, the results of crop safety assessment tests showed that D12 had no adverse effects on rice seed germination and seedling growth and development. The outcomes obtained from the present study suggested that D12 exhibited promise as a prospective antagonist of SL receptors, thereby displaying substantial efficacy in impeding the seed germination process of root parasitic weeds, providing a promising basis for rational design and development of further Striga-specific herbicides.
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Affiliation(s)
- Lin Du
- State Key Laboratory of Plant Environmental Resilience & Engineering Research Center of Plant Growth Regulator, MOE, College of Agronomy and Biotechnology, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, China
| | - Xingjia Li
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
| | - Yimin Ding
- State Key Laboratory of Plant Environmental Resilience & Engineering Research Center of Plant Growth Regulator, MOE, College of Agronomy and Biotechnology, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, China
| | - Dengke Ma
- State Key Laboratory of Plant Environmental Resilience & Engineering Research Center of Plant Growth Regulator, MOE, College of Agronomy and Biotechnology, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, China
| | - Chunxin Yu
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
| | - Liusheng Duan
- State Key Laboratory of Plant Environmental Resilience & Engineering Research Center of Plant Growth Regulator, MOE, College of Agronomy and Biotechnology, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
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3
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Lee H, Kim J, Koh M. Medium-Sized Ring Expansion Strategies: Enhancing Small-Molecule Library Development. Molecules 2024; 29:1562. [PMID: 38611841 PMCID: PMC11013129 DOI: 10.3390/molecules29071562] [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: 03/11/2024] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/14/2024] Open
Abstract
The construction of a small molecule library that includes compounds with medium-sized rings is increasingly essential in drug discovery. These compounds are essential for identifying novel therapeutic agents capable of targeting "undruggable" targets through high-throughput and high-content screening, given their structural complexity and diversity. However, synthesizing medium-sized rings presents notable challenges, particularly with direct cyclization methods, due to issues such as transannular strain and reduced degrees of freedom. This review presents an overview of current strategies in synthesizing medium-sized rings, emphasizing innovative approaches like ring-expansion reactions. It highlights the challenges of synthesis and the potential of these compounds to diversify the chemical space for drug discovery, underscoring the importance of medium-sized rings in developing new bioactive compounds.
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Affiliation(s)
- Hwiyeong Lee
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 46241, Republic of Korea;
| | - Jonghoon Kim
- Department of Chemistry and Integrative Institute of Basic Science, Soongsil University, Seoul 06978, Republic of Korea;
| | - Minseob Koh
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 46241, Republic of Korea;
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4
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Mallick RK, Žabka M, Clayden J. Benzo-fused Nitrogen Heterocycles by Asymmetric Ring Expansion and Stereochemically Retentive Re-contraction of Cyclic Ureas. Angew Chem Int Ed Engl 2024; 63:e202318417. [PMID: 38261257 DOI: 10.1002/anie.202318417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/12/2024] [Accepted: 01/22/2024] [Indexed: 01/24/2024]
Abstract
Benzo-fused nitrogen heterocycles are common features of bioactive molecules, and the enantioselective synthesis of their substituted analogues is an important goal. In this paper we demonstrate a practical and mechanistically intriguing approach to the enantioselective synthesis of 1-arylbenzazepines and their analogues. The reaction sequence starts with an asymmetric migratory ring expansion of indoline, tetrahydroquinoline, or tetrahydrobenzazepine ureas on treatment with a chiral lithium amide base. Treatment of the ring-expanded ureas with acid triggers a two-atom ring contraction-an 'azatropic shift' in which one urea nitrogen displaces the other-with almost complete retention of stereochemistry. Aminolysis of the urea products provides enantioenriched 1-aryl-tetrahydrobenzazepine derivatives and their congeners, including an analogue of an intermediate in the synthesis of the drug solifenacin. Deuteration, in situ IR, and DFT studies provide evidence for the mechanisms of the reaction steps.
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Affiliation(s)
- Rajendra K Mallick
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Matej Žabka
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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5
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Wang YJ, Zhao LM. Synthesis of 10-Membered Azecines through Pd-Catalyzed Formal [6+4] Cycloaddition and Their Transannular Reaction to Polycyclic Compounds. Chemistry 2023; 29:e202302111. [PMID: 37776147 DOI: 10.1002/chem.202302111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/17/2023] [Accepted: 09/25/2023] [Indexed: 10/01/2023]
Abstract
Azecine fragments are frequently presented in natural products and bioactive compounds. However, minor efforts have been devoted to these 10-membered N-heterocycles, and their synthesis is still challenging. Reported herein is the first catalytic formal [6+4] cycloaddition for the synthesis of 10-membered azecines. Under palladium catalysis, the reaction of δ-vinylvalerolactones and benzofuran-derived azadienes proceeds smoothly to afford benzofuran-fused azecines with high diastereoselectivity in moderate to good yields. A unique transannular reaction of these 10-membered azecines for the construction of polycyclic compounds is also demonstrated.
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Affiliation(s)
- Yu-Jiao Wang
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu, China
| | - Li-Ming Zhao
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu, China
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6
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Noor R, Zahoor AF, Mansha A, Khan SG, Haq AU, Ahmad S, Al-Hussain SA, Irfan A, Zaki MEA. Synthetic Potential of Regio- and Stereoselective Ring Expansion Reactions of Six-Membered Carbo- and Heterocyclic Ring Systems: A Review. Int J Mol Sci 2023; 24:ijms24076692. [PMID: 37047665 PMCID: PMC10094819 DOI: 10.3390/ijms24076692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/08/2023] [Accepted: 03/11/2023] [Indexed: 04/07/2023] Open
Abstract
Ring expansion reactions fascinate synthetic chemists owing to their importance in synthesizing biologically active compounds and their efficacy in medicinal chemistry. The present review summarizes a number of synthetic methodologies, including stereoselective and regioselective pathways adopted by scientists, for framing medium- to large-size carbo- and heterocycles involving lactams, lactone, azepine and azulene derivatives via ring expansion of six-membered carbo- and heterocycles that have been reported from 2007–2022. Numerous rearrangement and cycloaddition reactions involving Tiffeneau–Demjanov rearrangement, Aza–Claisen rearrangement, Schmidt rearrangement, Beckmann rearrangement, etc., have been described in this regard.
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Affiliation(s)
- Rida Noor
- Department of Chemistry, Government College, University Faisalabad, Faisalabad 38000, Pakistan
| | - Ameer Fawad Zahoor
- Department of Chemistry, Government College, University Faisalabad, Faisalabad 38000, Pakistan
| | - Asim Mansha
- Department of Chemistry, Government College, University Faisalabad, Faisalabad 38000, Pakistan
| | - Samreen Gul Khan
- Department of Chemistry, Government College, University Faisalabad, Faisalabad 38000, Pakistan
| | - Atta Ul Haq
- Department of Chemistry, Government College, University Faisalabad, Faisalabad 38000, Pakistan
| | - Sajjad Ahmad
- Department of Chemistry, University of Engineering and Technology Lahore, Faisalabad Campus, Faisalabad 38000, Pakistan
| | - Sami A. Al-Hussain
- Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia
| | - Ali Irfan
- Department of Chemistry, Government College, University Faisalabad, Faisalabad 38000, Pakistan
| | - Magdi E. A. Zaki
- Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia
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7
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Molnár Á. Recent Advances in the Synthesis of Five‐membered Nitrogen Heterocycles Induced by Palladium Ions and Complexes. ChemistrySelect 2023. [DOI: 10.1002/slct.202300153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- Árpád Molnár
- Department of Organic Chemistry University of Szeged Dóm tér 8 6720 Szeged Hungary
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8
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A Lewis Acid-Promoted Michael Addition and Ring-Expansion Cascade for the Construction of Nitrogen-Containing Medium-Sized Rings. Molecules 2023; 28:molecules28041650. [PMID: 36838638 PMCID: PMC9966210 DOI: 10.3390/molecules28041650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/03/2023] [Accepted: 02/04/2023] [Indexed: 02/11/2023] Open
Abstract
A Lewis acid-promoted annulation of azadienes and cyclobutamines was developed. This reaction proceeded through Michael addition and ring-expansion cascade, affording the corresponding nitrogen-containing medium-sized rings with a broad scope in moderate to high yields. The catalytic asymmetric version of this reaction has also been explored using a chiral base.
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9
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Xu H, Ma S. Palladium-Catalyzed [6+2] Double Allene Annulation for Benzazocines Synthesis. Angew Chem Int Ed Engl 2023; 62:e202213676. [PMID: 36372784 DOI: 10.1002/anie.202213676] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/07/2022] [Accepted: 11/11/2022] [Indexed: 11/15/2022]
Abstract
An efficient double allene protocol for the formation of benzazocines has been developed. The reaction constitutes a highly regioselective palladium-catalyzed formal [6+2] annulation of allenyl benzoxazinanones with terminal allenes forming the challenging 8-membered cycles. Decent yields and excellent regioselectivity have been observed under mild conditions with a remarkable Z-stereoselectivity for the exo-cyclic C=C bonds. The synthetic potentials of benzazocine products have been demonstrated.
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Affiliation(s)
- Haibo Xu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Shengming Ma
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, P. R. China.,Research Center for Molecular Recognition and Synthesis, Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, P. R. China
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10
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Li QZ, Guan YL, Huang QW, Qi T, Xiang P, Zhang X, Leng HJ, Li JL. Temperature-Controlled Divergent Asymmetric Synthesis of Indole-Based Medium-Sized Heterocycles through Palladium Catalysis. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Qing-Zhu Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy Chengdu University, Chengdu 610106, China
| | - Yi-Long Guan
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy Chengdu University, Chengdu 610106, China
| | - Qian-Wei Huang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy Chengdu University, Chengdu 610106, China
| | - Ting Qi
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy Chengdu University, Chengdu 610106, China
| | - Peng Xiang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy Chengdu University, Chengdu 610106, China
| | - Xiang Zhang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy Chengdu University, Chengdu 610106, China
| | - Hai-Jun Leng
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy Chengdu University, Chengdu 610106, China
| | - Jun-Long Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy Chengdu University, Chengdu 610106, China
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11
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Qin X, Zou N, Nong C, Mo D. Recent Advances on the Synthesis of Nine-Membered N-Heterocycles. CHINESE J ORG CHEM 2023. [DOI: 10.6023/cjoc202206035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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12
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Wales S, Saunthwal RK, Clayden J. C(sp 3)-Arylation by Conformationally Accelerated Intramolecular Nucleophilic Aromatic Substitution (S NAr). Acc Chem Res 2022; 55:1731-1747. [PMID: 35620846 PMCID: PMC9219115 DOI: 10.1021/acs.accounts.2c00184] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Indexed: 12/13/2022]
Abstract
The asymmetric synthesis of heavily substituted benzylic stereogenic centers, prevalent in natural products, therapeutics, agrochemicals, and catalysts, is an ongoing challenge. In this Account, we outline our contribution to this endeavor, describing our discovery of a series of new reactions that not only have synthetic applicability but also present significant mechanistic intrigue. The story originated from our longstanding interest in the stereochemistry and reactivity of functionalized organolithiums. While investigating the lithiation chemistry of ureas (a "Cinderella" sister of the more established amides and carbamates), we noted an unexpected Truce-Smiles (T-S) rearrangement involving the 1,4-N → C transposition of a urea N'-aryl group to the α-carbanion of an adjacent N-benzyl group. Despite this reaction formally constituting an SNAr substitution, we found it to be remarkably tolerant of the electronic properties of the migrating aryl substituent and the degree of substitution at the carbanion. Moreover, in contrast to classical SNAr reactions, the rearrangement was sufficiently rapid that it took place under conditions compatible with configurational stability in an organolithium intermediate, enabling enantiospecific arylation at benzylic stereogenic centers. Experimental and computational studies confirmed a low kinetic barrier to the aryl migration arising from the strong preference for a trans arrangement of the urea N'-aryl and carbonyl groups, populating a reactive conformer in which spatial proximity was enforced between the carbanion and N'-aryl group, hugely accelerating ipso-substitution.This discovery led us to uncover a whole series of conformationally accelerated intramolecular N → C aryl transfers using different anilide-based functional groups, including a diverse range of urea, carbamate, and thiocarbamate-substituted anions. Products included enantioenriched α-tertiary amines (including α-arylated N-heterocycles) and alcohols, as well as rare α-tertiary thiols. Synthetically challenging diarylated centers with differentiated aryl groups featured heavily in all product sets. The absolute enantiospecificity (retention versus inversion) of the reaction was dependent on the heteroatom α to the lithiation site: the origin of this stereodivergence was probed both experimentally and computationally. Asymmetric variants of the rearrangement were realized by enantioselective deprotonation, and connective strategies were developed in which an intermolecular C-C bond-forming event preceded the anionic rearrangement. Substrates where the N'-nucleofuge (at the aryl ipso position) was tethered to the migrating arene allowed us to use the rearrangement as a ring expansion method to generate 8- to 12-membered medium-ring N-heterocycles from very simple precursors. Stabilized carbon nucleophiles such as alkali metal enolates also readily promoted intramolecular N → C aryl transfer in N'-arylureas, opening up access to biologically relevant hydantoins, and enabling a "chiral memory" approach for the (hetero)arylation of chiral α-amino acids with programmable retention or inversion of configuration. Collectively, our studies of electronically versatile T-S rearrangements in anilide-based systems have culminated in a practical and general strategy for transition metal-free C(sp3)-arylation. More broadly, our results highlight the power of conformational activation to achieve unprecedented reactivity in the construction of challenging C-C bonds.
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Affiliation(s)
| | | | - Jonathan Clayden
- School of Chemistry, University
of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
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13
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Unsworth WP, Stephens TC. Strategies for the Synthesis of Heterocyclic Macrocycles and Medium‐Sized Rings. HETEROCYCLES 2022. [DOI: 10.1002/9783527832002.ch3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Palate KY, Yang Z, Whitwood AC, Unsworth WP. Synthesis of medium-ring lactams and macrocyclic peptide mimetics via conjugate addition/ring expansion cascade reactions. RSC Chem Biol 2022; 3:334-340. [PMID: 35359493 PMCID: PMC8905531 DOI: 10.1039/d1cb00245g] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/08/2022] [Indexed: 11/30/2022] Open
Abstract
A novel conjugate addition/ring expansion (CARE) cascade reaction sequence is reported that enables medium-sized ring and macrocyclic bis-lactams to be prepared from primary amines and cyclic imides. The reactions are simple to perform, generally high yielding, and very broad in scope, especially with respect to the primary amine component. CARE reactions can also be performed iteratively, enabling β-peptoid-based macrocyclic peptide mimetics to be ‘grown’ via well controlled, sequential 4-atom ring expansion reactions, with the incorporation of varied functionalised amines during each iteration. A conjugate addition/ring expansion (CARE) cascade reaction sequence is reported that enables medium-sized ring and macrocyclic bis-lactams to be prepared from primary amines and cyclic imides.![]()
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Affiliation(s)
- Kleopas Y Palate
- Department of Chemistry, University of York, Heslington York YO10 5DD UK
| | - Zhongzhen Yang
- Department of Chemistry, University of York, Heslington York YO10 5DD UK
| | - Adrian C Whitwood
- Department of Chemistry, University of York, Heslington York YO10 5DD UK
| | - William P Unsworth
- Department of Chemistry, University of York, Heslington York YO10 5DD UK
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15
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Qin X, Zou N, Cheng X, Liang C, Mo D. Synthesis of Chiral Nine‐Membered N‐Heterocycles through Silver(I)‐Promoted Cycloaddition and Rearrangement from
N
‐Vinyl‐α,β‐Unsaturated Nitrones with Chiral 3‐Propioloyloxazolidin‐2‐Ones. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202101199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Xiao‐Ting Qin
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources Collaborative Innovation Center for Guangxi Ethnic Medicine School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004, People's Republic of China
| | - Ning Zou
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources Collaborative Innovation Center for Guangxi Ethnic Medicine School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004, People's Republic of China
| | - Xiao‐Ling Cheng
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources Collaborative Innovation Center for Guangxi Ethnic Medicine School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004, People's Republic of China
| | - Cui Liang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources Collaborative Innovation Center for Guangxi Ethnic Medicine School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004, People's Republic of China
| | - Dong‐Liang Mo
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources Collaborative Innovation Center for Guangxi Ethnic Medicine School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004, People's Republic of China
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16
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Lee JY, Samala S, Kim J, Yoo EJ. Contractions of 1,4-Diazepines to Pyrroles Triggered by Valence Tautomerization: A One-Pot Approach and Mechanism. Org Lett 2021; 23:9006-9011. [PMID: 34752111 DOI: 10.1021/acs.orglett.1c03549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Herein, we describe the valence tautomerizations of fused 1,4-diazepines, which are reconstructed to give pyrrole derivatives and HCN gas. Several factors that influence the equilibrium between each valence tautomer of an 8π-electron diazepine skeleton are demonstrated. On the basis of these mechanistic studies, a cascade strategy for the construction of diazepines followed by ring contraction is developed to afford aryl- or alkyl-substituted pyrrolo[1,2-a]quinolines that are otherwise challenging to fabricate. In addition, further transformations of the obtained products highlight the advantages of the developed methodology.
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Affiliation(s)
- Ju Young Lee
- Department of Applied Chemistry, Kyung Hee University, Yongin 17104, Korea
| | - Srinivas Samala
- Department of Chemistry, Kangwon National University, Chuncheon 24341, Korea
| | - Jiyoung Kim
- Department of Applied Chemistry, Kyung Hee University, Yongin 17104, Korea
| | - Eun Jeong Yoo
- Department of Applied Chemistry, Kyung Hee University, Yongin 17104, Korea
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17
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Smith SN, Connon SJ. Preparation of Lactams from Cyclic Anhydrides
via N
‐Carboxyanhydride Intermediates. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Simon N. Smith
- School of Chemistry Trinity Biomedical Sciences Institute Trinity College Dublin 152-160 Pearse Street Dublin 2 Ireland
| | - Stephen J. Connon
- School of Chemistry Trinity Biomedical Sciences Institute Trinity College Dublin 152-160 Pearse Street Dublin 2 Ireland
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18
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Qiao J, Liu H, Wang S. Access to Indole-Annulated Medium-Sized Lactams through Protonation/Deuteration-Induced Ring-Opening of Spiroindolines. ACS OMEGA 2021; 6:25049-25061. [PMID: 34604684 PMCID: PMC8482774 DOI: 10.1021/acsomega.1c04261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Indexed: 06/13/2023]
Abstract
A protocol has been developed to access indole-annulated eight- and nine-membered lactams through protonation-induced ring-opening of spiroindolines, which are dearomative Heck products of tetrahydro-β-carbolines or hexahydroazepino[3,4-b]indoles. Brønsted acids and nucleophiles were explored and compared in the transformation. A combination of deuterated hydrochloride and deuterated methanol enables deuterative ring-opening of spiroindolines to afford medium-sized lactam diastereoisomers with a deuterium content ratio around 1:1.
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Affiliation(s)
- Jianhui Qiao
- State
Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of
Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Huili Liu
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Shaozhong Wang
- State
Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of
Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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19
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Loro C, Sala R, Penso M, Foschi F. DBU Catalysed Enantioselective Degradative Rearrangement: a Way to Tetrasubstituted 2‐Aryl‐2‐Amino Esters. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Camilla Loro
- Dipartimento di Scienza e Alta Tecnologia Università degli Studi dell'Insubria Via Valleggio 9 IT-20100 Como Italy
| | - Roberto Sala
- Dipartimento di Scienza e Alta Tecnologia Università degli Studi dell'Insubria Via Valleggio 9 IT-20100 Como Italy
| | - Michele Penso
- CNR-Istituto di Scienze e Tecnologie Chimiche “Giulio Natta” (SCITEC) Via Golgi 19 IT-20133 Milano Italy
| | - Francesca Foschi
- Dipartimento di Scienza e Alta Tecnologia Università degli Studi dell'Insubria Via Valleggio 9 IT-20100 Como Italy
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20
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Choi A, El‐Tunsi A, Wang Y, Meijer AJHM, Li J, Li X, Proietti Silvestri I, Coldham I. Asymmetric Synthesis of 2-Arylindolines and 2,2-Disubstituted Indolines by Kinetic Resolution. Chemistry 2021; 27:11670-11675. [PMID: 34110662 PMCID: PMC8456874 DOI: 10.1002/chem.202101248] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 01/18/2023]
Abstract
Kinetic resolution of 2-arylindolines (2,3-dihydroindoles) was achieved by treatment of their N-tert-butoxycarbonyl (Boc) derivatives with n-butyllithium and sparteine in toluene at -78 °C followed by electrophilic quench. The unreacted starting materials together with the 2,2-disubstituted products could be isolated with high enantiomer ratios. Variable temperature NMR spectroscopy showed that the rate of Boc rotation was fast (ΔG≠ ≈57 kJ/mol at 195 K). This was corroborated by DFT studies and by in situ ReactIR spectroscopy. The enantioenriched N-Boc-2-arylindolines were converted to 2,2-disubstituted products without significant loss in enantiopurity. Hence, either enantiomer of the 2,2-disubstituted products could be obtained with high selectivity from the same enantiomer of the chiral ligand sparteine (one from the kinetic resolution and the other from subsequent lithiation-trapping of the recovered starting material). Secondary amine products were prepared by removing the Boc group with acid to provide a way to access highly enantioenriched 2-aryl and 2,2-disubstituted indolines.
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Affiliation(s)
- Anthony Choi
- Department of ChemistryUniversity of Sheffield Brook HillSheffieldS3 7HFUK
| | - Ashraf El‐Tunsi
- Department of ChemistryUniversity of Sheffield Brook HillSheffieldS3 7HFUK
| | - Yuhang Wang
- Department of ChemistryUniversity of Sheffield Brook HillSheffieldS3 7HFUK
| | | | - Jia Li
- School of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi'an710062PR China
| | - Xiabing Li
- School of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi'an710062PR China
| | | | - Iain Coldham
- Department of ChemistryUniversity of Sheffield Brook HillSheffieldS3 7HFUK
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21
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Cao F, Gao W, Wang X, Zhang Z, Yin G, Wang Y, Li Z, Shi T, Hou Y, Chen J, Wang Z. Synthesis of the Proposed Structures of Parvistemoamide and Their Transformations to Stemoamide Derivatives. Org Lett 2021; 23:6222-6226. [PMID: 34369782 DOI: 10.1021/acs.orglett.1c01045] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The proposed structures of parvistemoamide have been achieved by macrolactamization, but none of the characterization data of synthetic samples matched with those of the natural sample. The transformation of the highly strained 10-membered lactam ring in parvistemoamide into the pyrrolo[1,2-a]-azepine nucleus in stemoamide is accomplished for the first time by either transannular cyclization or Pilli's transformation. This research may promote the total synthesis of other more complex stemoamide-type or medium-sized-ring-containing Stemona alkaloids.
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Affiliation(s)
- Fei Cao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Ministry of Education of China, Lanzhou 730000, Gansu, China
| | - Weiwei Gao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Ministry of Education of China, Lanzhou 730000, Gansu, China
| | - Xiaodong Wang
- School of Pharmacy, Lanzhou University, Ministry of Education of China, Number 199 West Donggang Road, Lanzhou 730000, Gansu, China
| | - Zhihan Zhang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Gaofeng Yin
- School of Pharmacy, Lanzhou University, Ministry of Education of China, Number 199 West Donggang Road, Lanzhou 730000, Gansu, China
| | - Yuqing Wang
- School of Pharmacy, Lanzhou University, Ministry of Education of China, Number 199 West Donggang Road, Lanzhou 730000, Gansu, China
| | - Zhao Li
- School of Pharmacy, Lanzhou University, Ministry of Education of China, Number 199 West Donggang Road, Lanzhou 730000, Gansu, China
| | - Tao Shi
- School of Pharmacy, Lanzhou University, Ministry of Education of China, Number 199 West Donggang Road, Lanzhou 730000, Gansu, China
| | - Yongsheng Hou
- School of Pharmacy, Lanzhou University, Ministry of Education of China, Number 199 West Donggang Road, Lanzhou 730000, Gansu, China
| | - Jinhong Chen
- School of Pharmacy, Lanzhou University, Ministry of Education of China, Number 199 West Donggang Road, Lanzhou 730000, Gansu, China
| | - Zhen Wang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Ministry of Education of China, Lanzhou 730000, Gansu, China.,School of Pharmacy, Lanzhou University, Ministry of Education of China, Number 199 West Donggang Road, Lanzhou 730000, Gansu, China
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22
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Yu B, Zou S, Huang H. Palladium-Catalyzed Ring-Closing Reaction for the Synthesis of Saturated N-Heterocycles with Aminodienes and N,O-Acetals. J Org Chem 2021; 86:7849-7863. [PMID: 34030442 DOI: 10.1021/acs.joc.1c00752] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An efficient palladium-catalyzed ring-closing reaction of aminodienes with N,O-acetals for the synthesis of saturated N-heterocycles is described. The reaction is consistently operated at room temperature and tolerates a wide range of functional groups with volatile MeOH as the sole byproduct. This method provides rapid and practical access to a broad range of saturated N-heterocycles with diverse structural backbones that are useful building blocks in natural product synthesis and drug discovery.
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Affiliation(s)
- Bangkui Yu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Suchen Zou
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Hanmin Huang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, 230026, P. R. China.,Center for Excellence in Molecular Synthesis of CAS, Hefei, 230026, P. R. China
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23
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Abrams R, Jesani MH, Browning A, Clayden J. Triarylmethanes and their Medium-Ring Analogues by Unactivated Truce-Smiles Rearrangement of Benzanilides. Angew Chem Int Ed Engl 2021; 60:11272-11277. [PMID: 33830592 PMCID: PMC8252078 DOI: 10.1002/anie.202102192] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/01/2021] [Indexed: 12/17/2022]
Abstract
Intramolecular nucleophilic aromatic substitution (Truce–Smiles rearrangement) of the anions of 2‐benzyl benzanilides leads to triarylmethanes in an operationally simple manner. The reaction succeeds even without electronic activation of the ring that plays the role of electrophile in the SNAr reaction, being accelerated instead by the preferred conformation imposed by the tertiary amide tether. The amide substituent of the product may be removed or transformed into alternative functional groups. A ring‐expanding variant (n to n+4) of the reaction provided a route to doubly benzo‐fused medium ring lactams of 10 or 11 members. Hammett analysis returned a ρ value consistent with the operation of a partially concerted reaction mechanism.
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Affiliation(s)
- Roman Abrams
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Mehul H Jesani
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Alex Browning
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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24
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Yang G, Ke Y, Zhao Y. Stereoselective Access to Polyfunctionalized Nine‐Membered Heterocycles by Sequential Gold and Palladium Catalysis. Angew Chem Int Ed Engl 2021; 60:12775-12780. [DOI: 10.1002/anie.202102061] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/28/2021] [Indexed: 11/05/2022]
Affiliation(s)
- Guoqiang Yang
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Ya‐Ming Ke
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Yu Zhao
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
- Joint School of National University of Singapore and Tianjin University International Campus of Tianjin University Binhai New City Fuzhou 350207 China
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25
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Yang G, Ke Y, Zhao Y. Stereoselective Access to Polyfunctionalized Nine‐Membered Heterocycles by Sequential Gold and Palladium Catalysis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102061] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Guoqiang Yang
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Ya‐Ming Ke
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Yu Zhao
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
- Joint School of National University of Singapore and Tianjin University International Campus of Tianjin University Binhai New City Fuzhou 350207 China
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26
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Sharma S, Singh J, Sharma A. Visible Light Assisted Radical‐Polar/Polar‐Radical Crossover Reactions in Organic Synthesis. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100205] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Shivani Sharma
- Department of Chemistry Indian Institute of Technology Roorkee Roorkee 247667 India
| | - Jitender Singh
- Department of Chemistry Indian Institute of Technology Roorkee Roorkee 247667 India
| | - Anuj Sharma
- Department of Chemistry Indian Institute of Technology Roorkee Roorkee 247667 India
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27
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Abrams R, Jesani MH, Browning A, Clayden J. Triarylmethanes and their Medium‐Ring Analogues by Unactivated Truce–Smiles Rearrangement of Benzanilides. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Roman Abrams
- School of Chemistry University of Bristol, Cantock's Close Bristol BS8 1TS UK
| | - Mehul H. Jesani
- School of Chemistry University of Bristol, Cantock's Close Bristol BS8 1TS UK
| | - Alex Browning
- School of Chemistry University of Bristol, Cantock's Close Bristol BS8 1TS UK
| | - Jonathan Clayden
- School of Chemistry University of Bristol, Cantock's Close Bristol BS8 1TS UK
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28
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Qiao J, Zhao W, Liang Y, Yao ZJ, Wang S. Diastereoselective Access to Tetracyclic Eight-Membered Lactams through a Dearomative Heck Reaction and an Alkylative Ring-Opening Driven by Photoexcited Spiroindolines. Chemistry 2021; 27:6308-6314. [PMID: 33506517 DOI: 10.1002/chem.202005369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/25/2021] [Indexed: 11/05/2022]
Abstract
An external-photocatalyst-free, light-driven alkylative ring-opening of stable spiroindolines was developed to construct indolo- and benzoannulated eight-membered lactams. The spiroindolines were prepared from tetrahydro-β-carbolines by a dearomative Heck reaction. Mechanistic experimental studies on the alkylative ring opening suggested that a photoredox pathway was involved, in which the spiroindoline performed as both reagent and photosensitizer. DFT calculations showed that the radical addition toward a cyclic alkene was the key to the diastereoselective formation of tetracyclic medium-sized lactams.
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Affiliation(s)
- Jianhui Qiao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Wenxuan Zhao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Yong Liang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Zhu-Jun Yao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Shaozhong Wang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
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29
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Mandal S, Banerjee J, Maity S, Chattopadhyay SK. Sequential Two‐Fold
Claisen
Rearrangement, One‐Pot Ring‐Closing Metathesis and Cross‐Metathesis as a Route to Substituted Benzo[
b
]azepine‐2‐one, Benzo[
b
]azepine and Benzo[
b
]oxepine Derivatives. Helv Chim Acta 2021. [DOI: 10.1002/hlca.202000216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Shyamasankar Mandal
- Department of Chemistry University of Kalyani Kalyani 741235 West Bengal India
| | - Jeet Banerjee
- Department of Chemistry University of Kalyani Kalyani 741235 West Bengal India
| | - Sougata Maity
- Department of Chemistry University of Kalyani Kalyani 741235 West Bengal India
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30
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Zheng H, Wang R, Wang K, Wherritt D, Arman H, Doyle MP. Formal [4 + 4]-, [4 + 3]-, and [4 + 2]-cycloaddition reactions of donor-acceptor cyclobutenes, cyclopropenes and siloxyalkynes induced by Brønsted acid catalysis. Chem Sci 2021; 12:4819-4824. [PMID: 34168758 PMCID: PMC8179600 DOI: 10.1039/d1sc00158b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 02/16/2021] [Indexed: 02/04/2023] Open
Abstract
Brønsted acid catalyzed formal [4 + 4]-, [4 + 3]-, and [4 + 2]-cycloadditions of donor-acceptor cyclobutenes, cyclopropenes, and siloxyalkynes with benzopyrylium ions are reported. [4 + 2]-cyclization/deMayo-type ring-extension cascade processes produce highly functionalized benzocyclooctatrienes, benzocycloheptatrienes, and 2-naphthols in good to excellent yields and selectivities. Moreover, the optical purity of reactant donor-acceptor cyclobutenes is fully retained during the cascade. The 1,3-dicarbonyl product framework of the reaction products provides opportunities for salen-type ligand syntheses and the construction of fused pyrazoles and isoxazoles that reveal a novel rotamer-diastereoisomerism.
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Affiliation(s)
- Haifeng Zheng
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Rui Wang
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Kan Wang
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Daniel Wherritt
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Hadi Arman
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Michael P Doyle
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
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31
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Palate KY, Epton RG, Whitwood AC, Lynam JM, Unsworth WP. Synthesis of macrocyclic and medium-sized ring thiolactones via the ring expansion of lactams. Org Biomol Chem 2021; 19:1404-1411. [PMID: 33491715 DOI: 10.1039/d0ob02502j] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A side chain insertion method for the ring expansion of lactams into macrocyclic thiolactones is reported, that can also be incorporated into Successive Ring Expansion (SuRE) sequences. The reactions are less thermodynamically favourable than the analogous lactam- and lactone-forming ring expansion processes (with this notion supported by DFT data), but nonetheless, three complementary protecting group strategies have been developed to enable this challenging transformation to be achieved.
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Affiliation(s)
- Kleopas Y Palate
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Ryan G Epton
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Adrian C Whitwood
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Jason M Lynam
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - William P Unsworth
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
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32
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Hu XQ, Liu ZK, Hou YX, Zhang G, Gao Y. Ru-catalysed C(sp 2)-H vinylation/annulation of benzoic acids and alkynes: rapid access to medium-sized lactones. Chem Commun (Camb) 2021; 57:1113-1116. [PMID: 33410434 DOI: 10.1039/d0cc07573f] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An unprecedented ruthenium catalysed [4+4] annulation of readily available benzoic acids and alkynes is reported for the first time. The carboxylate group acts as both a directing group and an internal nucleophilic reagent to facilitate a C(sp2)-H vinylation/annulation cascade. This reaction avoids the classically oxidative [4+2] annulation, allowing the efficient synthesis of a wide array of eight-membered lactones under oxidant-free conditions. Moreover, this catalytic system can be successfully extended to [4+3] and [4+5] annulations for the assembly of seven- and nine-membered lactones.
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Affiliation(s)
- Xiao-Qiang Hu
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science, School of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074, China.
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33
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Shang J, Thombare VJ, Charron CL, Wille U, Hutton CA. Ring Expansion of Thiolactams via Imide Intermediates: An Amino Acid Insertion Strategy. Chemistry 2021; 27:1620-1625. [PMID: 33289186 DOI: 10.1002/chem.202005035] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Indexed: 12/22/2022]
Abstract
The AgI -promoted reaction of thiolactams with N-Boc amino acids yields an N-(α-aminoacyl) lactam that can rearrange through an acyl transfer process. Boc-deprotection results in convergence to the ring-expanded adduct, thereby facilitating an overall insertion of an amino acid into the thioamide bond to generate medium-sized heterocycles. Application to the site-specific insertion of amino acids into cyclic peptides is demonstrated.
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Affiliation(s)
- Jing Shang
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic 3010, Australia
| | - Varsha J Thombare
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic 3010, Australia
| | - Carlie L Charron
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic 3010, Australia
| | - Uta Wille
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic 3010, Australia
| | - Craig A Hutton
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic 3010, Australia
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34
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Du J, Yang X, Wang X, An Q, He X, Pan H, Zuo Z. Photocatalytic Aerobic Oxidative Ring Expansion of Cyclic Ketones to Macrolactones by Cerium and Cyanoanthracene Catalysis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202012720] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jianbo Du
- School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China
- University of Chinese Academy of Science Beijing 100049 China
| | - Xiaokun Yang
- School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China
- University of Chinese Academy of Science Beijing 100049 China
| | - Xin Wang
- School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China
- University of Chinese Academy of Science Beijing 100049 China
| | - Qing An
- School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China
- University of Chinese Academy of Science Beijing 100049 China
| | - Xu He
- School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China
- University of Chinese Academy of Science Beijing 100049 China
| | - Hui Pan
- School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China
- University of Chinese Academy of Science Beijing 100049 China
| | - Zhiwei Zuo
- State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China
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35
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Du J, Yang X, Wang X, An Q, He X, Pan H, Zuo Z. Photocatalytic Aerobic Oxidative Ring Expansion of Cyclic Ketones to Macrolactones by Cerium and Cyanoanthracene Catalysis. Angew Chem Int Ed Engl 2021; 60:5370-5376. [PMID: 33259085 DOI: 10.1002/anie.202012720] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/16/2020] [Indexed: 12/17/2022]
Abstract
We describe a cerium-catalyzed aerobic oxidative ring expansion for the expedient construction of synthetically challenging macrolactones under visible-light conditions. Cyanoanthracene has been employed as co-catalyst to accelerate the turnover of the cerium cycle leading to a fast conversion within 20 min of irradiation. Taking advantage of the high efficiency and operationally simple conditions, a collection of over 100 macrolactones equipped with ring systems ranging from 9- to 19-membered macrocycles have been prepared from simple building blocks. Moreover, the enabling potential of this strategy to simplify the generation of molecular complexity has been demonstrated through the concise synthesis of sonnerlactone.
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Affiliation(s)
- Jianbo Du
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Science, Beijing, 100049, China
| | - Xiaokun Yang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Science, Beijing, 100049, China
| | - Xin Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Science, Beijing, 100049, China
| | - Qing An
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Science, Beijing, 100049, China
| | - Xu He
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Science, Beijing, 100049, China
| | - Hui Pan
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Science, Beijing, 100049, China
| | - Zhiwei Zuo
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
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36
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Zhang X, Lin L, Li J, Duan S, Long Y, Li J. Recent Progress in the Synthesis of Medium-Sized Ring and Macrocyclic Compounds. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202010026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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37
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Millward MJ, Ellis E, Ward JW, Clayden J. Hydantoin-bridged medium ring scaffolds by migratory insertion of urea-tethered nitrile anions into aromatic C-N bonds. Chem Sci 2020; 12:2091-2096. [PMID: 34163972 PMCID: PMC8179327 DOI: 10.1039/d0sc06188c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/11/2020] [Indexed: 01/07/2023] Open
Abstract
Bicyclic or tricyclic nitrogen-containing heterocyclic scaffolds were constructed rapidly by intramolecular nucleophilic aromatic substitution of metallated nitriles tethered by a urea linkage to a series of electronically unactivated heterocyclic precursors. The substitution reaction constitutes a ring expansion, enabled by the conformationally constrained tether between the nitrile and the heterocycle. Attack of the metallated urea leaving group on the nitrile generates a hydantoin that bridges the polycyclic products. X-ray crystallography reveals ring-dependant strain within the hydantoin.
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Affiliation(s)
- Makenzie J Millward
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Emily Ellis
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - John W Ward
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
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39
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Lawer A, Epton RG, Stephens TC, Palate KY, Lodi M, Marotte E, Lamb KJ, Sangha JK, Lynam JM, Unsworth WP. Evaluating the Viability of Successive Ring-Expansions Based on Amino Acid and Hydroxyacid Side-Chain Insertion. Chemistry 2020; 26:12674-12683. [PMID: 32432817 PMCID: PMC7589337 DOI: 10.1002/chem.202002164] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Indexed: 01/20/2023]
Abstract
The outcome of ring-expansion reactions based on amino/hydroxyacid side-chain insertion is strongly dependent on ring size. This manuscript, which builds upon our previous work on Successive Ring Expansion (SuRE) methods, details efforts to better define the scope and limitations of these reactions on lactam and β-ketoester ring systems with respect to ring size and additional functionality. The synthetic results provide clear guidelines as to which substrate classes are more likely to be successful and are supported by computational results, using a density functional theory (DFT) approach. Calculating the relative Gibbs free energies of the three isomeric species that are formed reversibly during ring expansion enables the viability of new synthetic reactions to be correctly predicted in most cases. The new synthetic and computational results are expected to support the design of new lactam- and β-ketoester-based ring-expansion reactions.
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Affiliation(s)
- Aggie Lawer
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
| | - Ryan G. Epton
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
| | | | | | - Mahendar Lodi
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
| | - Emilie Marotte
- ENSICAEN6 Boulevard Maréchal Juin, CS 4505314050Caen Cedex 04France
| | - Katie J. Lamb
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
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40
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Srinivasulu V, Schilf P, Ibrahim S, Shehadi IA, Malik OG, Sieburth S, Khanfar MA, Hamad M, Abu-Yousef IA, Majdalawieh AF, Al-Tel TH. Divergent Strategy for Diastereocontrolled Synthesis of Small- and Medium-Ring Architectures. J Org Chem 2020; 85:10695-10708. [PMID: 32806094 DOI: 10.1021/acs.joc.0c01244] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nitrogen and oxygen medium rings, in particular nine-membered rings, epitomize a unique area of chemical space that occurs in many natural products and biologically appealing compounds. The scarcity of 8- to 12-membered rings among clinically approved drugs is indicative of the difficulties associated with their synthesis, principally owing to the unfavorable entropy and transannular strain. We report here a scandium triflate-catalyzed reaction that allows for a modular access to a diverse collection of nine-membered ring heterocycles in a one-pot cascade and with complete diastereocontrol. This cascade features an intramolecular addition of an acyl group-derived enol to a α,β-unsaturated carbonyl moiety, leading to N- and O-derived medium-ring systems. Computational studies using the density functional theory support the proposed mechanism. Additionally, a one-pot cascade leading to hexacyclic chromeno[3',4':2,3]indolizino[8,7-b]indole architectures, with six fused rings and four contiguous chiral centers, is reported. This novel cascade features many concerted events, including the formation of two azomethine ylides, [3 + 2]-cycloaddition, 1,3-sigmatropic rearrangement, Michael addition, and Pictet-Spengler reaction among others. Phenotypic screening of the resulting oxazonine collection identified chemical probes that regulate mitochondrial membrane potential, adenosine 5'-triphosphate contents, and reactive oxygen species levels in hepatoma cells (Hepa1-6), a promising approach for targeting cancer and metabolic disorders.
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Affiliation(s)
- Vunnam Srinivasulu
- Sharjah Institute for Medical Research, University of Sharjah, P.O. Box 27272, Sharjah, UAE
| | - Paul Schilf
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Ratzeburger Allee 160, Lübeck 23538, Germany
| | - Saleh Ibrahim
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Ratzeburger Allee 160, Lübeck 23538, Germany
| | - Ihsan A Shehadi
- College of Science, Department of Chemistry, University of Sharjah, P.O. Box 27272, Sharjah, UAE
| | - Omar G Malik
- College of Science, Department of Chemistry, University of Sharjah, P.O. Box 27272, Sharjah, UAE
| | - Scott Sieburth
- Department of Chemistry, Temple University, 201 Beury Hall, Philadelphia, Pennsylvania 19122, United States
| | - Monther A Khanfar
- College of Science, Department of Chemistry, University of Sharjah, P.O. Box 27272, Sharjah, UAE.,Department of Chemistry, University of Jordan, Amman 11942, Jordan
| | - Mohamad Hamad
- College of Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, UAE
| | - Imad A Abu-Yousef
- Department of Biology, Chemistry and Environmental Sciences, American University of Sharjah, P.O. Box 26666, Sharjah, UAE
| | - Amin F Majdalawieh
- Department of Biology, Chemistry and Environmental Sciences, American University of Sharjah, P.O. Box 26666, Sharjah, UAE
| | - Taleb H Al-Tel
- Sharjah Institute for Medical Research, University of Sharjah, P.O. Box 27272, Sharjah, UAE
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41
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Abrams R, Clayden J. Photocatalytic Difunctionalization of Vinyl Ureas by Radical Addition Polar Truce–Smiles Rearrangement Cascades. Angew Chem Int Ed Engl 2020; 59:11600-11606. [DOI: 10.1002/anie.202003632] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Indexed: 02/03/2023]
Affiliation(s)
- Roman Abrams
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Jonathan Clayden
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
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42
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Abrams R, Clayden J. Photocatalytic Difunctionalization of Vinyl Ureas by Radical Addition Polar Truce–Smiles Rearrangement Cascades. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003632] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Roman Abrams
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Jonathan Clayden
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
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43
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Yuan Y, Guo Z, Mu Y, Wang Y, Xu M, Li Y. Synthesis of Spiro[5.n (n=6–8)]heterocycles through Successive Ring‐Expansion/Indole C‐2 Functionalization. Adv Synth Catal 2020. [DOI: 10.1002/adsc.201901631] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Yang Yuan
- School of Chemistry and Molecular EngineeringEast China Normal University 500 Dongchuan Road Shanghai 200241 People's Republic of China
| | - Zixia Guo
- School of Chemistry and Molecular EngineeringEast China Normal University 500 Dongchuan Road Shanghai 200241 People's Republic of China
| | - Yuanyang Mu
- School of Chemistry and Molecular EngineeringEast China Normal University 500 Dongchuan Road Shanghai 200241 People's Republic of China
| | - Ye Wang
- School of Chemistry and Molecular EngineeringEast China Normal University 500 Dongchuan Road Shanghai 200241 People's Republic of China
| | - Murong Xu
- School of Chemistry and Molecular EngineeringEast China Normal University 500 Dongchuan Road Shanghai 200241 People's Republic of China
| | - Yanzhong Li
- School of Chemistry and Molecular EngineeringEast China Normal University 500 Dongchuan Road Shanghai 200241 People's Republic of China
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44
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Clarke AK, Unsworth WP. A happy medium: the synthesis of medicinally important medium-sized rings via ring expansion. Chem Sci 2020; 11:2876-2881. [PMID: 34122787 PMCID: PMC8152702 DOI: 10.1039/d0sc00568a] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Medium-sized rings have much promise in medicinal chemistry, but are difficult to make using direct cyclisation methods. In this minireview, we highlight the value of ring expansion strategies to address this long-standing synthetic challenge. We have drawn on recent progress (post 2013) to highlight the key reaction design features that enable successful ‘normal-to-medium’ ring expansion for the synthesis of these medicinally important molecular frameworks, that are currently under-represented in compound screening collections and marketed drugs in view of their challenging syntheses. Ring expansion strategies are ideally suited to make synthetically challenging, medium-sized rings with much potential in medicinal chemistry.![]()
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Affiliation(s)
- Aimee K Clarke
- Department of Chemistry, University of York York YO10 5DD UK
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45
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Kurouchi H, Ohwada T. Synthesis of Medium-Ring-Sized Benzolactams by Using Strong Electrophiles and Quantitative Evaluation of Ring-Size Dependency of the Cyclization Reaction Rate. J Org Chem 2020; 85:876-901. [PMID: 31800245 DOI: 10.1021/acs.joc.9b02843] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Benzolactams with medium-sized rings were synthesized via the electrophilic aromatic substitution reaction of carbamoyl cations (R1R2N+═C═O) in good to high yields without dilution. These reactions were utilized to quantitatively examine the extent of retardation of medium-sized ring formation, compared to five- or six-membered ring formation. The order of reaction rates of formation of cyclic benzolactams is six- > five- > seven- > eight- > nine-membered ring at 25 °C. The present reaction provides a route to eight- and nine-membered benzolactams.
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Affiliation(s)
- Hiroaki Kurouchi
- Research Foundation Itsuu Laboratory , C1232, Kanagawa Science Park R&D Building, 3-2-1 Sakado , Takatsu-ku, Kawasaki , Kanagawa 213-0012 , Japan.,Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
| | - Tomohiko Ohwada
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
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46
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Abstract
While the bottom-up design of enzymes appears to be an intractably complex problem, a minimal approach that combines elementary, de novo-designed proteins with intrinsically reactive cofactors offers a simple means to rapidly access sophisticated catalytic mechanisms. Not only is this method proven in the reproduction of powerful oxidative chemistry of the natural peroxidase enzymes, but we show here that it extends to the efficient, abiological—and often asymmetric—formation of strained cyclopropane rings, nitrogen–carbon and carbon–carbon bonds, and the ring expansion of a simple cyclic molecule to form a precursor for NAD+, a fundamentally important biological cofactor. That the enzyme also functions in vivo paves the way for its incorporation into engineered biosynthetic pathways within living organisms. By constructing an in vivo-assembled, catalytically proficient peroxidase, C45, we have recently demonstrated the catalytic potential of simple, de novo-designed heme proteins. Here, we show that C45’s enzymatic activity extends to the efficient and stereoselective intermolecular transfer of carbenes to olefins, heterocycles, aldehydes, and amines. Not only is this a report of carbene transferase activity in a completely de novo protein, but also of enzyme-catalyzed ring expansion of aromatic heterocycles via carbene transfer by any enzyme.
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47
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Beng TK, Garcia J, Smith M, Orellana AO. Skeletal remodelling of α-substituted cyclic eneformamides to α-ketonyl cyclic amines. NEW J CHEM 2020. [DOI: 10.1039/d0nj02768e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A modular dehomologation strategy, which skeletally remodels cyclic α-substituted eneformamides to one-carbon shorter α-ketonyl saturated cyclic amines is described.
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Affiliation(s)
- Timothy K. Beng
- Department of Chemistry
- Central Washington University
- Ellensburg
- USA
| | - Jorge Garcia
- Department of Chemistry
- Central Washington University
- Ellensburg
- USA
| | - Meagan Smith
- Department of Chemistry
- Central Washington University
- Ellensburg
- USA
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48
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Ma X, Nong C, Zhao J, Lu X, Liang C, Mo D. Yb(OTf)
3
‐Catalyzed Cycloaddition/[3,3]‐Rearrangement of
N
‐Vinyl‐α,β‐Unsaturated Ketonitrones with Methylenecycloprop‐anes: Stereoselective Synthesis of Nine‐Membered Nitrogen Heterocycles. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201901206] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Xiao‐Pan Ma
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Education of China; School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004 People's Republic of China
| | - Cai‐Mei Nong
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Education of China; School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004 People's Republic of China
| | - Jie Zhao
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Education of China; School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004 People's Republic of China
| | - Xiuqiang Lu
- Fuqing Branch of Fujian Normal University, Fuzhou Fujian 350300 People's Republic of China
| | - Cui Liang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Education of China; School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004 People's Republic of China
| | - Dong‐Liang Mo
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Education of China; School of Chemistry and Pharmaceutical Sciences Guangxi Normal University 15 Yu Cai Road Guilin 541004 People's Republic of China
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49
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Dierks A, Tönjes J, Schmidtmann M, Christoffers J. Synthesis of Benzo[b]azocin-2-ones by Aryl Amination and Ring-Expansion of α-(Iodophenyl)-β-oxoesters. Chemistry 2019; 25:14912-14920. [PMID: 31433088 PMCID: PMC6899745 DOI: 10.1002/chem.201903139] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Indexed: 01/16/2023]
Abstract
Transformation of β-oxoesters with PhI(OCOCF3 )2 leads to α-(ortho-iodophenyl)-β-oxoesters. These materials are the starting point for the synthesis of 6-carboxybenzo[b]azocin-2-ones by a sequence of aryl amination and ring transformation. This reaction sequence starts with copper-catalyzed formation of N-alkyl anilines from the iodoarenes and primary amines in the presence of K3 PO4 as stoichiometric base. The intermediate products underwent ring transformation by addition of the nitrogen into the carbonyl group of the cycloalkanone, furnishing benzo-annulated eight-membered ring lactams. Under the same reaction conditions, the cyclohexanone and cycloheptanone derivatives gave no aminated products, but ring-transformed to benzofuran derivatives. The title compounds of this investigation contain two points for further diversification (the lactam nitrogen and the carboxylate function), thus, the suitability of this compound class as a scaffold was proven by appropriate functionalizations. The first series of derivatizations of the scaffold was initiated by hydrogenolytic debenzylation of N-benzyl derivative to provide the NH-congener, which could be deprotonated with LDA and alkylated at nitrogen to give further examples of this compound class. Secondly, the ester function was submitted to saponification and the resulting carboxylic acid could be amidated using HATU as coupling reagent to furnish different amides.
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Affiliation(s)
- Anna Dierks
- Institut für ChemieCarl von Ossietzky Universität Oldenburg26111OldenburgGermany
| | - Jan Tönjes
- Institut für ChemieCarl von Ossietzky Universität Oldenburg26111OldenburgGermany
| | - Marc Schmidtmann
- Institut für ChemieCarl von Ossietzky Universität Oldenburg26111OldenburgGermany
| | - Jens Christoffers
- Institut für ChemieCarl von Ossietzky Universität Oldenburg26111OldenburgGermany
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50
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Rohrbach S, Smith AJ, Pang JH, Poole DL, Tuttle T, Chiba S, Murphy JA. Concerted Nucleophilic Aromatic Substitution Reactions. Angew Chem Int Ed Engl 2019; 58:16368-16388. [PMID: 30990931 PMCID: PMC6899550 DOI: 10.1002/anie.201902216] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/11/2019] [Indexed: 12/31/2022]
Abstract
Recent developments in experimental and computational chemistry have identified a rapidly growing class of nucleophilic aromatic substitutions that proceed by concerted (cSN Ar) rather than classical, two-step, SN Ar mechanisms. Whereas traditional SN Ar reactions require substantial activation of the aromatic ring by electron-withdrawing substituents, such activating groups are not mandatory in the concerted pathways.
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Affiliation(s)
- Simon Rohrbach
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Andrew J. Smith
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Jia Hao Pang
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore
| | - Darren L. Poole
- GlaxoSmithKline Medicines Research CentreGunnels Wood RoadStevenageSG1 2NYUK
| | - Tell Tuttle
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Shunsuke Chiba
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore
| | - John A. Murphy
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
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