1
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McCann S, Roe WE, Agnew HE, Knipe PC. Non-Covalent Interactions Enforce Conformation in Switchable and Water-Soluble Diketopiperazine-Pyridine Foldamers. Angew Chem Int Ed Engl 2023; 62:e202307180. [PMID: 37414732 PMCID: PMC10952507 DOI: 10.1002/anie.202307180] [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: 05/22/2023] [Revised: 07/05/2023] [Accepted: 07/06/2023] [Indexed: 07/08/2023]
Abstract
To reach their potential as mimics of the dynamic molecules present in biological systems, foldamers must be designed to display stimulus-responsive behavior. Here we report such a foldamer architecture based on alternating pyridine-diketopiperazine linkers. Epimerization is conveniently prevented through a copper-catalyzed coupling protocol. The compounds' native unswitched conformation is first discovered in the solid and solution state. The foldamers can be solubilized in DMSO and pH 9.5 buffer, retaining conformational control to a large degree. Lastly, dynamic switching is demonstrated through treatment with acid, leading to behaviour we describe as stimulus-responsive sidechain reconfiguration.
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Affiliation(s)
- Sinead McCann
- School of Chemistry and Chemical EngineeringQueen's University BelfastDavid Keir Building, Stranmillis RoadBelfastBT9 5AGUK
| | - William E. Roe
- School of Chemistry and Chemical EngineeringQueen's University BelfastDavid Keir Building, Stranmillis RoadBelfastBT9 5AGUK
| | - Hannah E. Agnew
- School of Chemistry and Chemical EngineeringQueen's University BelfastDavid Keir Building, Stranmillis RoadBelfastBT9 5AGUK
| | - Peter C. Knipe
- School of Chemistry and Chemical EngineeringQueen's University BelfastDavid Keir Building, Stranmillis RoadBelfastBT9 5AGUK
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2
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Roe WE, Warnock TMC, Knipe PC. A spirocyclic backbone accesses new conformational space in an extended, dipole-stabilized foldamer. Commun Chem 2023; 6:71. [PMID: 37069245 PMCID: PMC10110530 DOI: 10.1038/s42004-023-00868-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 03/24/2023] [Indexed: 04/19/2023] Open
Abstract
Most aromatic foldamers adopt uniform secondary structures, offering limited potential for the exploration of conformational space and the formation of tertiary structures. Here we report the incorporation of spiro bis-lactams to allow controlled rotation of the backbone of an iteratively synthesised foldamer. This enables precise control of foldamer shape along two orthogonal directions, likened to the aeronautical yaw and roll axes. XRD, NMR and computational data suggest that homo-oligomers adopt an extended right-handed helix with a pitch of over 30 Å, approximately that of B-DNA. Compatibility with extant foldamers to form hetero-oligomers is demonstrated, allowing greater structural complexity and function in future hybrid foldamer designs.
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Affiliation(s)
- William Edward Roe
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK
| | - Toyah Mary Catherine Warnock
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK
| | - Peter Clarke Knipe
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK.
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3
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Zhang L, Liu C, Sun M, Liang C, Cao L, Yao X, Ma Y, Cheng R, Ye J. Iridium-Catalyzed Asymmetric Hydrogenation of Simple Ketones with Tridentate PNN Ligands Bearing Unsymmetrical Vicinal Diamines. J Org Chem 2023. [PMID: 36787380 DOI: 10.1021/acs.joc.2c02676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
An iridium catalytic system with a ferrocene-based phosphine ligand bearing a modular and tunable unsymmetrical vicinal diamine scaffold was developed for the asymmetric hydrogenation of aryl ketones. This approach provided a powerful tool for the enantioselective synthesis of diverse chiral alcohols with excellent reactivity and enantioselectivity (up to 99% yield, up to 99% ee, and up to 50,000 turnover number). The substituents and chirality of unsymmetrical diamines in ligands played an important role in the satisfactory results.
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Affiliation(s)
- Lei Zhang
- Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Chengyu Liu
- Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Maolin Sun
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Chaoming Liang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Liming Cao
- Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Xiantong Yao
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Yueyue Ma
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Ruihua Cheng
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Jinxing Ye
- Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.,School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
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4
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Lei T, Cheng YY, Han X, Zhou C, Yang B, Fan XW, Chen B, Tung CH, Wu LZ. Lewis Acid-Relayed Singlet Oxygen Reaction with Enamines: Selective Dimerization of Enamines to Pyrrolin-4-ones. J Am Chem Soc 2022; 144:16667-16675. [PMID: 36047993 DOI: 10.1021/jacs.2c07450] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Singlet oxygen (1O2)-mediated oxidation represents an attractive strategy for incorporation of oxygen atoms from air under mild and environmentally benign conditions. However, the 1O2 reaction with enamine suffers from fragmentation, leading to very unsuccessful transformation. Here, Lewis acid is introduced to intercept [2 + 2] or "ene" reaction intermediates of the 1O2 reaction and enables oxidative dimerization of enamines to produce pyrrolin-4-ones in good to excellent yields. Mechanistic studies reveal the formation of the imino ketone intermediate from the interaction of 1O2 and enamine, which is able to interact with Lewis acid, relaying the 1O2 reaction in enamine chemistry. For the first time, selective cross-dimerization of two different enamines is achieved. Due to the advantages of mild conditions, high chemoselectivity, and up to 99% yield, a promising strategy has been developed for synthesizing aza-heterocycles under ambient conditions, which can be further applied for the synthesis of imidazolone, quinoxaline, and highly functionalized imine.
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Affiliation(s)
- Tao Lei
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yuan-Yuan Cheng
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xu Han
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Chao Zhou
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Bing Yang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xiu-Wei Fan
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Bin Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Chen-Ho Tung
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Li-Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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5
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Warnock TMC, Rajkumar S, Fitzpatrick MP, Serpell CJ, Dingwall P, Knipe PC. Chiral, sequence-definable foldamer-derived macrocycles. Chem Sci 2021; 12:15632-15636. [PMID: 35003593 PMCID: PMC8654020 DOI: 10.1039/d1sc05021d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/03/2021] [Indexed: 12/22/2022] Open
Abstract
Nature's oligomeric macromolecules have been a long-standing source of inspiration for chemists producing foldamers. Natural systems are frequently conformationally stabilised by macrocyclisation, yet this approach has been rarely adopted in the field of foldamer chemistry. Here we present a new class of chiral cyclic trimers and tetramers formed by macrocyclisation of open-chain foldamer precursors. Symmetrical products are obtained via a [2 + 2] self-assembly approach, while full sequence control is demonstrated through linear synthesis and cyclisation of an unsymmetrical trimer. Structural characterisation is achieved through a combined X-ray and DFT approach, which indicates the tetramers adopt a near-planar conformation, while the trimers adopt a shallow bowl-like shape. Finally, a proof-of-concept experiment is conducted to demonstrate the macrocycles' capacity for cation binding. Dipole-controlled pre-organization enables the cyclization of sequence-defined foldamers into macrocycles. The structure and properties of trimeric and tetrameric macrocycles are explored, and their ability to bind cationic guests is demonstrated.![]()
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Affiliation(s)
- Toyah M C Warnock
- School of Chemistry and Chemical Engineering, Queen's University Belfast David Keir Building Belfast BT9 5AG UK
| | | | - Matthew P Fitzpatrick
- School of Chemistry and Chemical Engineering, Queen's University Belfast David Keir Building Belfast BT9 5AG UK
| | - Christopher J Serpell
- School of Physical Sciences, University of Kent Ingram Building Canterbury Kent CT2 7NH UK
| | - Paul Dingwall
- School of Chemistry and Chemical Engineering, Queen's University Belfast David Keir Building Belfast BT9 5AG UK
| | - Peter C Knipe
- School of Chemistry and Chemical Engineering, Queen's University Belfast David Keir Building Belfast BT9 5AG UK
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6
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Arrata I, Grison CM, Coubrough HM, Prabhakaran P, Little MA, Tomlinson DC, Webb ME, Wilson AJ. Control of conformation in α-helix mimicking aromatic oligoamide foldamers through interactions between adjacent side-chains. Org Biomol Chem 2019; 17:3861-3867. [PMID: 30938392 DOI: 10.1039/c9ob00123a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The design, synthesis and structural characterization of non-natural oligomers that adopt well-defined conformations, so called foldamers, is a key objective in developing biomimetic 3D functional architectures. For the aromatic oligoamide foldamer family, use of interactions between side-chains to control conformation is underexplored. The current manuscript addresses this objective through the design, synthesis and conformational analyses of model dimers derived from 3-O-alkylated para-aminobenzoic acid monomers. The O-alkyl groups on these foldamers are capable of adopting syn- or anti-conformers through rotation around the Ar-CO/NH axes. In the syn-conformation this allows the foldamer to act as a topographical mimic of the α-helix whereby the O-alkyl groups mimic the spatial orientation of the i and i + 4 side-chains from the α-helix. Using molecular modelling and 2D NMR analyses, this work illustrates that covalent links and hydrogen-bonding interactions between side-chains can bias the conformation in favour of the α-helix mimicking syn-conformer, offering insight that may be more widely applied to control secondary structure in foldamers.
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Affiliation(s)
- Irene Arrata
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK.
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7
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Recent Advances in the Catalytic Synthesis of Imidazolidin-2-ones and Benzimidazolidin-2-ones. Catalysts 2019. [DOI: 10.3390/catal9010028] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
2-Imidazolidinone and its analogues are omnipresent structural motifs of pharmaceuticals, natural products, chiral auxiliaries, and intermediates in organic syntheses. Over the years, continuous efforts have been addressed to the development of sustainable and more efficient protocols for the synthesis of these heterocycles. This review gives a summary of the catalytic strategies to access imidazolidin-2-ones and benzimidazolidin-2-ones that have appeared in the literature from 2010 to 2018. Particularly important contributions beyond the timespan will be mentioned. The review is organized in four main chapters that identify the most common approaches to imidazolidin-2-one derivatives: (1) the direct incorporation of the carbonyl group into 1,2-diamines, (2) the diamination of olefins, (3) the intramolecular hydroamination of linear urea derivatives and (4) aziridine ring expansion. Methods not included in this classification will be addressed in the miscellaneous section.
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8
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Lockhart Z, Knipe PC. Conformationally Programmable Chiral Foldamers with Compact and Extended Domains Controlled by Monomer Structure. Angew Chem Int Ed Engl 2018; 57:8478-8482. [PMID: 29737622 PMCID: PMC6055681 DOI: 10.1002/anie.201802822] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/24/2018] [Indexed: 11/17/2022]
Abstract
Foldamers are an important class of abiotic macromolecules, with potential therapeutic applications in the disruption of protein–protein interactions. The majority adopt a single conformational motif such as a helix. A class of foldamer is now introduced where the choice of heterocycle within each monomer, coupled with a strong conformation‐determining dipole repulsion effect, allows both helical and extended conformations to be selected. Combining these monomers into hetero‐oligomers enables highly controlled exploration of conformational space and projection of side‐chains along multiple vectors. The foldamers were rapidly constructed via an iterative deprotection‐cross‐coupling sequence, and their solid‐ and solution‐phase conformations were analysed by X‐ray crystallography and NMR and CD spectroscopy. These molecules may find applications in protein surface recognition where the interface does not involve canonical peptide secondary structures.
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Affiliation(s)
- Zachariah Lockhart
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK
| | - Peter C Knipe
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK
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