1
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Rowett AC, Sweeting SG, Heard DM, Lennox AJJ. A Stoichiometric Haloform Coupling for Ester Synthesis with Secondary Alcohols. Angew Chem Int Ed Engl 2024:e202400570. [PMID: 38533790 DOI: 10.1002/anie.202400570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 03/28/2024]
Abstract
The haloform reaction from methyl ketones to carboxylic acids is one of the oldest known synthetic organic reactions, which has been used in myriad applications over the decades. The corresponding reaction to produce esters is, however, less developed, as the reaction is generally limited to simple, primary alcohols that are used in solvent-level quantities, thereby restricting the complexity of esters that can be directly formed. Herein, we detail the development of a general ester-forming haloform coupling reaction using one equivalent of alcohol. Mechanistic and kinetic modelling studies demonstrated that the key intermediates are formed under equilibrium, which facilitated the development of conditions that are amenable to secondary alcohols.
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Affiliation(s)
- Albert C Rowett
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Stephen G Sweeting
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - David M Heard
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Alastair J J Lennox
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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2
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Atkins AP, Chaturvedi AK, Tate JA, Lennox AJJ. Pulsed electrolysis: enhancing primary benzylic C(sp 3)-H nucleophilic fluorination. Org Chem Front 2024; 11:802-808. [PMID: 38298566 PMCID: PMC10825853 DOI: 10.1039/d3qo01865b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 12/09/2023] [Indexed: 02/02/2024]
Abstract
Electrosynthesis is an efficient and powerful tool for the generation of elusive reactive intermediates. The application of alternative electrolysis waveforms provides a new level of control for dynamic redox environments. Herein, we demonstrate that pulsed electrolysis provides a favourable environment for the generation and fluorination of highly unstable primary benzylic cations from C(sp3)-H bonds. By introduction of a toff period, we propose this waveform modulates the electrical double layer to improve mass transport and limit over-oxidation.
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Affiliation(s)
- Alexander P Atkins
- School of Chemistry, University of Bristol Cantock's Close BS8 1TS Bristol UK
| | - Atul K Chaturvedi
- School of Chemistry, University of Bristol Cantock's Close BS8 1TS Bristol UK
| | - Joseph A Tate
- Jealott's Hill International Research Centre, Syngenta Jealott's Hill Bracknell RG426EY UK
| | - Alastair J J Lennox
- School of Chemistry, University of Bristol Cantock's Close BS8 1TS Bristol UK
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3
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Choi A, Goodrich OH, Atkins AP, Edwards MD, Tiemessen D, George MW, Lennox AJJ. Electrochemical Benzylic C(sp 3)-H Direct Amidation. Org Lett 2024; 26:653-657. [PMID: 38227550 PMCID: PMC10825869 DOI: 10.1021/acs.orglett.3c04012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/30/2023] [Accepted: 01/03/2024] [Indexed: 01/17/2024]
Abstract
Amide bonds are ubiquitous and found in a myriad of functional molecules. Although formed in a reliable and robust fashion, alternative amide bond disconnections provide flexibility and synthetic control. Herein we describe an electrochemical method to form the non-amide C-N bond from direct benzylic C(sp3)-H amidation. Our approach is applied toward the synthesis of secondary amides by coupling secondary benzylic substrates with substituted primary benzamides. The reaction has been scaled up to a multigram scale in flow.
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Affiliation(s)
- Anthony Choi
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
| | | | | | | | - David Tiemessen
- School
of Chemistry, University of Nottingham, Nottingham NG7 2RD, U.K.
| | - Michael W. George
- School
of Chemistry, University of Nottingham, Nottingham NG7 2RD, U.K.
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4
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Stammers E, Parsons CD, Clayden J, Lennox AJJ. Electrochemical synthesis of biaryls by reductive extrusion from N,N'-diarylureas. Nat Commun 2023; 14:4561. [PMID: 37507363 PMCID: PMC10382484 DOI: 10.1038/s41467-023-40237-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
The synthesis of biaryl compounds by the transition-metal free coupling of arenes is an important contemporary challenge, aiming to avoid the toxicity and cost profiles associated with the metal catalysts commonly used in the synthesis of these pharmaceutically relevant motifs. In this paper, we describe an electrochemical approach to the synthesis of biaryls in which aniline derivatives are coupled through the formation and reduction of a temporary urea linkage. The conformational alignment of the arenes in the N,N'-diaryl urea intermediates promotes C-C bond formation following single-electron reduction. Our optimized conditions are suitable for the synthesis of a variety of biaryls, including sterically hindered examples carrying ortho-substituents, representing complementary reactivity to most metal catalysed methods.
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Affiliation(s)
- Ellie Stammers
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Chris D Parsons
- Early Chemical Development, Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield, SK10 2NA, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
| | - Alastair J J Lennox
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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5
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Box JR, Avanthay ME, Poole DL, Lennox AJJ. Electronically Ambivalent Hydrodefluorination of Aryl‐CF 3 groups enabled by Electrochemical Deep‐Reduction on a Ni Cathode. Angew Chem Int Ed Engl 2023; 62:e202218195. [PMID: 36705627 PMCID: PMC10946569 DOI: 10.1002/anie.202218195] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/27/2023] [Accepted: 01/27/2023] [Indexed: 01/28/2023]
Abstract
We report a general procedure for the direct mono- and di-hydrodefluorination of ArCF3 compounds. Exploiting the tunability of electrochemistry and the selectivity enabled by a Ni cathode, the deep reduction garners high selectivity with good to excellent yields up to gram scale. The late-stage peripheral editing of CF3 feedstocks to construct fluoromethyl moieties will aid the rapid diversification of lead-compounds and compound libraries.
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Affiliation(s)
- John R. Box
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | | | - Darren L. Poole
- Discovery High-Throughput ChemistryMedicinal ChemistryGSK Medicines Research CentreStevenageSG1 2NYUK
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6
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Abstract
The development of sustainable C(sp3)-H functionalization methods is of great interest to the pharmaceutical and agrochemical industries. Anodic oxidation is an efficient means of producing benzylic cations that can undergo subsequent in situ nucleophilic attack to afford functionalized benzylic products. Herein, we demonstrate the suitability of carboxylic acids as nucleophiles to yield benzylic esters. This method employs a series of secondary benzylic substrates and functionalized carboxylic acids and is demonstrated on a gram scale in flow.
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Affiliation(s)
- Alexander P Atkins
- University of Bristol, School of Chemistry, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Albert C Rowett
- University of Bristol, School of Chemistry, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - David M Heard
- University of Bristol, School of Chemistry, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Joseph A Tate
- Syngenta, Jealott's Hill International Research Centre, Bracknell RG42 6EY, United Kingdom
| | - Alastair J J Lennox
- University of Bristol, School of Chemistry, Cantock's Close, Bristol BS8 1TS, United Kingdom
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7
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Avanthay M, Bedford RB, Begg CS, Böse D, Clayden J, Davis SA, Eloi JC, Goryunov GP, Hartung IV, Heeley J, Khaikin KA, Kitching MO, Krieger J, Kulyabin PS, Lennox AJJ, Nolla-Saltiel R, Pridmore NE, Rowsell BJS, Sparkes HA, Uborsky DV, Voskoboynikov AZ, Walsh MP, Wilkinson HJ. Identifying palladium culprits in amine catalysis. Nat Catal 2021. [DOI: 10.1038/s41929-021-00710-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Doobary S, Poole DL, Lennox AJJ. Intramolecular Alkene Fluoroarylation of Phenolic Ethers Enabled by Electrochemically Generated Iodane. J Org Chem 2021; 86:16095-16103. [PMID: 34766770 DOI: 10.1021/acs.joc.1c01946] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The 3-substituted chromane core is found in several bioactive natural products. Herein, we describe a route to 3-fluorinated chromanes from allylic phenol ethers. Our external oxidant-free approach takes advantage of an electrochemical generation of a hypervalent iodine species, difluoro-λ3-tolyl iodane, which mediates the alkene fluoroarylation. High yields and selectivity for this transformation are achieved for electron poor substrates. The redox chemistry has been characterized for the electrochemical generation of the iodane in the presence of fluoride, and insights into the mechanism are given. The transformation has been demonstrated on gram scales, which indicates the potential broader utility of the process.
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Affiliation(s)
- Sayad Doobary
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Darren L Poole
- Medicines Design, GSK Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Alastair J J Lennox
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
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9
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Elliott LD, Booker-Milburn KI, Lennox AJJ. Daisy-Chaining Photo- and Thermal Chemistry: Multistep Continuous Flow Synthesis of Visible-Light-Mediated Photochemistry with a High-Temperature Cascade Reaction. Org Process Res Dev 2021. [DOI: 10.1021/acs.oprd.1c00187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Luke D. Elliott
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
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10
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Box JR, Atkins AP, Lennox AJJ. Direct electrochemical hydrodefluorination of trifluoromethylketones enabled by non-protic conditions. Chem Sci 2021; 12:10252-10258. [PMID: 34377412 PMCID: PMC8336478 DOI: 10.1039/d1sc01574e] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 06/22/2021] [Indexed: 12/20/2022] Open
Abstract
CF2H groups are unique due to the combination of their lipophilic and hydrogen bonding properties. The strength of H-bonding is determined by the group to which it is appended. Several functional groups have been explored in this context including O, S, SO and SO2 to tune the intermolecular interaction. Difluoromethyl ketones are under-studied in this context, without a broadly accessible method for their preparation. Herein, we describe the development of an electrochemical hydrodefluorination of readily accessible trifluoromethylketones. The single-step reaction at deeply reductive potentials is uniquely amenable to challenging electron-rich substrates and reductively sensitive functionality. Key to this success is the use of non-protic conditions enabled by an ammonium salt that serves as a reductively stable, masked proton source. Analysis of their H-bonding has revealed difluoromethyl ketones to be potentially highly useful dual H-bond donor/acceptor moieties. The electrochemical hydrodefluorination of trifluoromethylketones under non-protic conditions make this single-step reaction at deeply reductive potentials uniquely amenable to challenging electron-rich substrates and reductively sensitive functionalities.![]()
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Affiliation(s)
- John R Box
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Alexander P Atkins
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Alastair J J Lennox
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
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11
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Affiliation(s)
- David M. Heard
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS
| | - Sayad Doobary
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS
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12
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Heard DM, Lennox AJJ. Dichloromeldrum's Acid (DiCMA): A Practical and Green Amine Dichloroacetylation Reagent. Org Lett 2021; 23:3368-3372. [PMID: 33844547 DOI: 10.1021/acs.orglett.1c00850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dichloromeldrum's acid is introduced as a bench-stable, nonvolatile reagent for the dichloroacetylation of anilines and alkyl amines to produce α,α-dichloroacetamides, which are important motifs for medicinal chemistry. Products are formed in good to excellent yields with reagent grade solvents, and, as the only byproducts are acetone and CO2, no column chromatography is required. Thus, this reagent is practical, efficient, and green for the dichloroacetylation of primary amines.
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Affiliation(s)
- David M Heard
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, U.K
| | - Alastair J J Lennox
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, U.K
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13
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Abstract
The choice of electrode material is critical for achieving optimal yields and selectivity in synthetic organic electrochemistry. The material imparts significant influence on the kinetics and thermodynamics of electron transfer, and frequently defines the success or failure of a transformation. Electrode processes are complex and so the choice of a material is often empirical and the underlying mechanisms and rationale for success are unknown. In this review, we aim to highlight recent instances of electrode choice where rationale is offered, which should aid future reaction development.
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Affiliation(s)
- David M. Heard
- University of BristolSchool of ChemistryCantocks CloseBristol, AvonBS8 1TSUK
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14
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Affiliation(s)
- David M. Heard
- University of Bristol School of Chemistry Cantocks Close Bristol, Avon BS8 1TS UK
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15
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Jing C, Mallah S, Kriemen E, Bennett SH, Fasano V, Lennox AJJ, Hers I, Aggarwal VK. Synthesis, Stability, and Biological Studies of Fluorinated Analogues of Thromboxane A 2. ACS Cent Sci 2020; 6:995-1000. [PMID: 32607446 PMCID: PMC7318075 DOI: 10.1021/acscentsci.0c00310] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Indexed: 06/11/2023]
Abstract
Platelet activation results in the generation of thromboxane A2 (TxA2), which promotes thrombus formation by further amplifying platelet function, as well as causing vasoconstriction. Due to its role in thrombus formation and cardiovascular disease, its production is the target of antiplatelet drugs such as aspirin. However, the study of TxA2-stimulated cellular function has been limited by its instability (t 1/2 = 32 s, pH = 7.4). Although more stable analogues such as U46619 and difluorinated 10,10-F2-TxA2 have been prepared, we targeted a closer mimic to TxA2 itself, monofluorinated 10-F-TxA2, since the number of fluorine atoms can affect function. Key steps in the synthesis of F-TxA2 included α-fluorination of a lactone bearing a β-alkoxy group, and a novel synthesis of the strained acetal. F-TxA2 was found to be 105 more stable than TxA2, and surprisingly was only slightly less stable than F2-TxA2. Preliminary biological studies showed that F-TxA2 has similar potency as TxA2 toward inducing platelet aggregation but was superior to F2-TxA2 in activating integrin αIIbβ3.
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Affiliation(s)
- Changcheng Jing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Shahida Mallah
- School
of Physiology, Pharmacology & Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Ella Kriemen
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Steven H. Bennett
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Valerio Fasano
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Alastair J. J. Lennox
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Ingeborg Hers
- School
of Physiology, Pharmacology & Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Varinder K. Aggarwal
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
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16
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Abstract
Vicinal difluorinated alkanes are entities relevant to medicinal chemistry that are accessed through the difluorination of alkenes. This reaction has advanced from the use of highly reactive and unsafe reagents, which provide poor functional-group tolerance and selectivity, to the use of safer and more selective reagents that facilitate access to a broader scope of substrates. In this review article, we describe the details of these developments.1 Introduction2 Strategy 1: Ambiphilic Fluorine Sources3 Strategy 2: Oxidant and Fluoride4 Conclusions and Outlook
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17
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Doobary S, Sedikides AT, Caldora HP, Poole DL, Lennox AJJ. Electrochemical Vicinal Difluorination of Alkenes: Scalable and Amenable to Electron‐Rich Substrates. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201912119] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sayad Doobary
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Alexi T. Sedikides
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Henry P. Caldora
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Darren L. Poole
- Medicines Design GSK Medicines Research Centre Gunnels Wood Rd Stevenage SG1 2NY UK
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18
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Doobary S, Sedikides AT, Caldora HP, Poole DL, Lennox AJJ. Electrochemical Vicinal Difluorination of Alkenes: Scalable and Amenable to Electron-Rich Substrates. Angew Chem Int Ed Engl 2019; 59:1155-1160. [PMID: 31697872 PMCID: PMC6973232 DOI: 10.1002/anie.201912119] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 11/06/2019] [Indexed: 01/16/2023]
Abstract
Fluorinated alkyl groups are important motifs in bioactive compounds, positively influencing pharmacokinetics, potency and conformation. The oxidative difluorination of alkenes represents an important strategy for their preparation, yet current methods are limited in their alkene‐types and tolerance of electron‐rich, readily oxidized functionalities, as well as in their safety and scalability. Herein, we report a method for the difluorination of a number of unactivated alkene‐types that is tolerant of electron‐rich functionality, giving products that are otherwise unattainable. Key to success is the electrochemical generation of a hypervalent iodine mediator using an “ex‐cell” approach, which avoids oxidative substrate decomposition. The more sustainable conditions give good to excellent yields in up to decagram scales.
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Affiliation(s)
- Sayad Doobary
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Alexi T Sedikides
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Henry P Caldora
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Darren L Poole
- Medicines Design, GSK Medicines Research Centre, Gunnels Wood Rd, Stevenage, SG1 2NY, UK
| | - Alastair J J Lennox
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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19
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20
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Affiliation(s)
- Alastair J. J. Lennox
- School of Chemistry; University of Bristol; Cantocks Close Bristol, Avon BS8 1TS Großbritannien
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21
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Luo SP, Wang XJ, Chen H, Yu ZJ, Lou WY, Xia LM, Lou BY, Liu XF, Kang P, Lennox AJJ, Wu QA. Cover Feature: Structural Design of Conjugated Poly (ferrocene-phenanthroline) for Photocatalytic Hydrogen Evolution from Water (ChemPhotoChem 9/2018). CHEMPHOTOCHEM 2018. [DOI: 10.1002/cptc.201800175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Shu-Ping Luo
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Xiao-Jing Wang
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Hao Chen
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Zhe-Jian Yu
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Wen-Ya Lou
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Liang-Min Xia
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Bai-Yang Lou
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Xue-Fen Liu
- Qiangjiang College; Hangzhou Normal University; 310012 Hangzhou China
| | - Peng Kang
- School of Chemical Engineering and Technology; Tianjin University; 300072 Tianjin China
| | | | - Qing-An Wu
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
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22
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Lennox AJJ, Goes SL, Webster MP, Koolman HF, Djuric SW, Stahl SS. Electrochemical Aminoxyl-Mediated α-Cyanation of Secondary Piperidines for Pharmaceutical Building Block Diversification. J Am Chem Soc 2018; 140:11227-11231. [PMID: 30141925 DOI: 10.1021/jacs.8b08145] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Secondary piperidines are ideal pharmaceutical building blocks owing to the prevalence of piperidines in commercial drugs. Here, we report an electrochemical method for cyanation of the heterocycle adjacent to nitrogen without requiring protection or substitution of the N-H bond. The reaction utilizes ABNO (9-azabicyclononane N-oxyl) as a catalytic mediator. Electrochemical oxidation of ABNO generates the corresponding oxoammonium species, which promotes dehydrogenation of the 2° piperidine to the cyclic imine, followed by addition of cyanide. The low-potential, mediated electrolysis process is compatible with a wide range of heterocyclic and oxidatively sensitive substituents on the piperidine ring and enables synthesis of unnatural amino acids.
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Affiliation(s)
- Alastair J J Lennox
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Shannon L Goes
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Matthew P Webster
- AbbVie, Global Pharmaceutical R&D , 1 North Waukegan Road , North Chicago , Illinois 60064 , United States
| | - Hannes F Koolman
- AbbVie, Global Pharmaceutical R&D , 1 North Waukegan Road , North Chicago , Illinois 60064 , United States
| | - Stevan W Djuric
- AbbVie, Global Pharmaceutical R&D , 1 North Waukegan Road , North Chicago , Illinois 60064 , United States
| | - Shannon S Stahl
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
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23
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Luo SP, Wang XJ, Chen H, Yu ZJ, Lou WY, Xia LM, Lou BY, Liu XF, Kang P, Lennox AJJ, Wu QA. Structural Design of Conjugated Poly (ferrocene-phenanthroline) for Photocatalytic Hydrogen Evolution from Water. CHEMPHOTOCHEM 2018. [DOI: 10.1002/cptc.201800070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Shu-Ping Luo
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Xiao-Jing Wang
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Hao Chen
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Zhe-Jian Yu
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Wen-Ya Lou
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Liang-Min Xia
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Bai-Yang Lou
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Xue-Fen Liu
- Qiangjiang College; Hangzhou Normal University; 310012 Hangzhou China
| | - Peng Kang
- School of Chemical Engineering and Technology; Tianjin University; 300072 Tianjin China
| | | | - Qing-An Wu
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
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24
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Lennox AJJ, Nutting JE, Stahl SS. Selective electrochemical generation of benzylic radicals enabled by ferrocene-based electron-transfer mediators. Chem Sci 2018; 9:356-361. [PMID: 29732109 PMCID: PMC5909123 DOI: 10.1039/c7sc04032f] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 10/25/2017] [Indexed: 11/25/2022] Open
Abstract
The generation and intermolecular functionalisation of carbon-centred radicals has broad potential synthetic utility. Herein, we show that benzylic radicals may be generated electrochemically from benzylboronate derivatives at low electrode potentials (ca. -0.3 V vs. Cp2Fe0/+) via single electron oxidation. Use of a catalytic quantity of a ferrocene-based electron-transfer mediator is crucial to achieve successful radical functionalisation and avoid undesirable side reactions arising from direct electrochemical oxidation or from the use of stoichiometric ferrocenium-based oxidants.
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Affiliation(s)
- Alastair J J Lennox
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , USA .
| | - Jordan E Nutting
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , USA .
| | - Shannon S Stahl
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , USA .
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25
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Chen NY, Xia LM, Lennox AJJ, Sun YY, Chen H, Jin HM, Junge H, Wu QA, Jia JH, Beller M, Luo SP. Structure-Activated Copper Photosensitisers for Photocatalytic Water Reduction. Chemistry 2017; 23:3631-3636. [DOI: 10.1002/chem.201602598] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 11/27/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Nan-Yu Chen
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; Chaowang Road 18 310014 Hangzhou P.R. China
| | - Liang-Min Xia
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; Chaowang Road 18 310014 Hangzhou P.R. China
| | - Alastair J. J. Lennox
- Leibniz-Institut für Katalyse an der; Universität Rostock e.V.; Albert-Einstein-Strasse 29a 18059 Rostock Germany
| | - Yuan-Yuan Sun
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; Chaowang Road 18 310014 Hangzhou P.R. China
| | - Hao Chen
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; Chaowang Road 18 310014 Hangzhou P.R. China
| | - Hai-Ming Jin
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; Chaowang Road 18 310014 Hangzhou P.R. China
| | - Henrik Junge
- Leibniz-Institut für Katalyse an der; Universität Rostock e.V.; Albert-Einstein-Strasse 29a 18059 Rostock Germany
| | - Qin-An Wu
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; Chaowang Road 18 310014 Hangzhou P.R. China
| | - Jian-Hong Jia
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; Chaowang Road 18 310014 Hangzhou P.R. China
| | - Matthias Beller
- Leibniz-Institut für Katalyse an der; Universität Rostock e.V.; Albert-Einstein-Strasse 29a 18059 Rostock Germany
| | - Shu-Ping Luo
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; Chaowang Road 18 310014 Hangzhou P.R. China
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26
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Priebe JB, Radnik J, Kreyenschulte C, Lennox AJJ, Junge H, Beller M, Brückner A. H2Generation with (Mixed) Plasmonic Cu/Au-TiO2Photocatalysts: Structure-Reactivity Relationships Assessed by in situ Spectroscopy. ChemCatChem 2017. [DOI: 10.1002/cctc.201601361] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jacqueline B. Priebe
- Leibniz Institute for Catalysis at the University of Rostock (LIKAT); Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Jörg Radnik
- Federal Institute for Materials Research (BAM); Unter den Eichen 44-46 12203 Berlin Germany
| | - Carsten Kreyenschulte
- Leibniz Institute for Catalysis at the University of Rostock (LIKAT); Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Alastair J. J. Lennox
- Department of Chemistry; University of Wisconsin Madison; 1101 University Ave Madison WI 53706 USA
| | - Henrik Junge
- Leibniz Institute for Catalysis at the University of Rostock (LIKAT); Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Matthias Beller
- Leibniz Institute for Catalysis at the University of Rostock (LIKAT); Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Angelika Brückner
- Leibniz Institute for Catalysis at the University of Rostock (LIKAT); Albert-Einstein-Str. 29a 18059 Rostock Germany
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27
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Alberico E, Lennox AJJ, Vogt LK, Jiao H, Baumann W, Drexler HJ, Nielsen M, Spannenberg A, Checinski MP, Junge H, Beller M. Unravelling the Mechanism of Basic Aqueous Methanol Dehydrogenation Catalyzed by Ru-PNP Pincer Complexes. J Am Chem Soc 2016; 138:14890-14904. [PMID: 27759392 DOI: 10.1021/jacs.6b05692] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ruthenium PNP complex 1a (RuH(CO)Cl(HN(C2H4Pi-Pr2)2)) represents a state-of-the-art catalyst for low-temperature (<100 °C) aqueous methanol dehydrogenation to H2 and CO2. Herein, we describe an investigation that combines experiment, spectroscopy, and theory to provide a mechanistic rationale for this process. During catalysis, the presence of two anionic resting states was revealed, Ru-dihydride (3-) and Ru-monohydride (4-) that are deprotonated at nitrogen in the pincer ligand backbone. DFT calculations showed that O- and CH- coordination modes of methoxide to ruthenium compete, and form complexes 4- and 3-, respectively. Not only does the reaction rate increase with increasing KOH, but the ratio of 3-/4- increases, demonstrating that the "inner-sphere" C-H cleavage, via C-H coordination of methoxide to Ru, is promoted by base. Protonation of 3- liberates H2 gas and formaldehyde, the latter of which is rapidly consumed by KOH to give the corresponding gem-diolate and provides the overall driving force for the reaction. Full MeOH reforming is achieved through the corresponding steps that start from the gem-diolate and formate. Theoretical studies into the mechanism of the catalyst Me-1a (N-methylated 1a) revealed that C-H coordination to Ru sets-up C-H cleavage and hydride delivery; a process that is also promoted by base, as observed experimentally. However, in this case, Ru-dihydride Me-3 is much more stable to protonation and can even be observed under neutral conditions. The greater stability of Me-3 rationalizes the lower rates of Me-1a compared to 1a, and also explains why the reaction rate then drops with increasing KOH concentration.
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Affiliation(s)
- Elisabetta Alberico
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany.,Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche , tr. La Crucca 3, 07100 Sassari, Italy
| | - Alastair J J Lennox
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany
| | - Lydia K Vogt
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany
| | - Haijun Jiao
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany
| | - Wolfgang Baumann
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany
| | - Hans-Joachim Drexler
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany
| | - Martin Nielsen
- Centre for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark , Kemitorvet 207, 2800 Kgs. Lyngby, Denmark
| | - Anke Spannenberg
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany
| | | | - Henrik Junge
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany
| | - Matthias Beller
- Leibniz Institute for Catalysis, University of Rostock , Albert Einstein-Straße 29a, 18059 Rostock, Germany
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28
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Sun YY, Wang H, Chen NY, Lennox AJJ, Friedrich A, Xia LM, Lochbrunner S, Junge H, Beller M, Zhou S, Luo SP. Efficient Photocatalytic Water Reduction Using In Situ Generated Knölker's Iron Complexes. ChemCatChem 2016. [DOI: 10.1002/cctc.201600186] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yuan-Yuan Sun
- State Key Laboratory Breeding Base of Green Chemistry-, Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Hai Wang
- Key Laboratory of Pesticide & Chemical Biology; Ministry of Education; College of Chemistry; Central China Normal University; 430079 Wuhan China
| | - Nan-Yu Chen
- State Key Laboratory Breeding Base of Green Chemistry-, Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Alastair J J Lennox
- State Key Laboratory Breeding Base of Green Chemistry-, Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
- Leibniz-Institut für Katalyse an der Universität Rostock e.V.; Albert-Einstein-Straße 29a 18059 Rostock Germany
| | - Aleksej Friedrich
- Institute of Physics; University of Rostock; Albert-Einstein-Straße 23 18059 Rostock Germany
| | - Liang-Min Xia
- State Key Laboratory Breeding Base of Green Chemistry-, Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
| | - Stefan Lochbrunner
- Institute of Physics; University of Rostock; Albert-Einstein-Straße 23 18059 Rostock Germany
| | - Henrik Junge
- Leibniz-Institut für Katalyse an der Universität Rostock e.V.; Albert-Einstein-Straße 29a 18059 Rostock Germany
| | - Matthias Beller
- Leibniz-Institut für Katalyse an der Universität Rostock e.V.; Albert-Einstein-Straße 29a 18059 Rostock Germany
| | - Shaolin Zhou
- Key Laboratory of Pesticide & Chemical Biology; Ministry of Education; College of Chemistry; Central China Normal University; 430079 Wuhan China
| | - Shu-Ping Luo
- State Key Laboratory Breeding Base of Green Chemistry-, Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou China
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29
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Lennox AJJ, Fischer S, Jurrat M, Luo SP, Rockstroh N, Junge H, Ludwig R, Beller M. Copper-Based Photosensitisers in Water Reduction: A More Efficient In Situ Formed System and Improved Mechanistic Understanding. Chemistry 2015; 22:1233-8. [DOI: 10.1002/chem.201503812] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Indexed: 11/05/2022]
Affiliation(s)
- Alastair J. J. Lennox
- Leibniz Institute for Catalysis at the; University of Rostock; Albert Einstein-Straße 29a 18059 Rostock Germany
| | - Steffen Fischer
- Institute of Chemistry; Department Physical Chemistry; University of Rostock; Dr. Lorenz-Weg 1 18059 Rostock Germany
| | - Mark Jurrat
- Leibniz Institute for Catalysis at the; University of Rostock; Albert Einstein-Straße 29a 18059 Rostock Germany
| | - Shu-Ping Luo
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology; Zhejiang University of Technology; 310014 Hangzhou P.R. China
| | - Nils Rockstroh
- Leibniz Institute for Catalysis at the; University of Rostock; Albert Einstein-Straße 29a 18059 Rostock Germany
| | - Henrik Junge
- Leibniz Institute for Catalysis at the; University of Rostock; Albert Einstein-Straße 29a 18059 Rostock Germany
| | - Ralf Ludwig
- Institute of Chemistry; Department Physical Chemistry; University of Rostock; Dr. Lorenz-Weg 1 18059 Rostock Germany
| | - Matthias Beller
- Leibniz Institute for Catalysis at the; University of Rostock; Albert Einstein-Straße 29a 18059 Rostock Germany
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30
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Pospech J, Lennox AJJ, Beller M. Rhodium-catalysed alkoxylation/acetalization of diazo compounds: one-step synthesis of highly functionalised quaternary carbon centres. Chem Commun (Camb) 2015; 51:14505-8. [PMID: 26280033 DOI: 10.1039/c5cc03903g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An intermolecular tandem reaction for the rapid build-up of densely functionalised α-alkoxy-β-oxo-esters has been developed. This novel process applies the easy to handle trimethyl orthoformate as a C1-building block in the rhodium(II)-catalysed alkoxylation/acetalization of donor-acceptor substituted diazo compounds. The concomitant C-O/C-C bond formation reaction gives products with unique quaternary carbon centers, substituted by groups of different oxidation level (ester, protected aldehyde and alkoxide).
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Affiliation(s)
- Jola Pospech
- Leibniz-Institute for Catalysis at the University of Rostock, Albert-Einstein-Strasse 29a, D-18059 Rostock, Germany.
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31
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Priebe JB, Radnik J, Lennox AJJ, Pohl MM, Karnahl M, Hollmann D, Grabow K, Bentrup U, Junge H, Beller M, Brückner A. Solar Hydrogen Production by Plasmonic Au–TiO2 Catalysts: Impact of Synthesis Protocol and TiO2 Phase on Charge Transfer Efficiency and H2 Evolution Rates. ACS Catal 2015. [DOI: 10.1021/cs5018375] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Jacqueline B. Priebe
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Jörg Radnik
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Alastair J. J. Lennox
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Marga-Martina Pohl
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Michael Karnahl
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Dirk Hollmann
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Kathleen Grabow
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Ursula Bentrup
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Henrik Junge
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Matthias Beller
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Angelika Brückner
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
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32
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Bornschein C, Lennox AJJ, Werkmeister S, Junge K, Beller M. A Mild and Selective Reduction of β-Lactams: Rh-Catalyzed Hydrosilylation towards Important Pharmacological Building Blocks. European J Org Chem 2015. [DOI: 10.1002/ejoc.201403655] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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33
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34
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35
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Lennox AJJ, Lloyd-Jones GC. Transmetalation in the Suzuki-Miyaura Coupling: The Fork in the Trail. Angew Chem Int Ed Engl 2013; 52:7362-70. [DOI: 10.1002/anie.201301737] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Indexed: 11/12/2022]
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36
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Lennox AJJ, Lloyd-Jones GC. Preparation of Organotrifluoroborate Salts: Precipitation-Driven Equilibrium under Non-Etching Conditions. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201203930] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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37
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Lennox AJJ, Lloyd-Jones GC. Preparation of Organotrifluoroborate Salts: Precipitation-Driven Equilibrium under Non-Etching Conditions. Angew Chem Int Ed Engl 2012; 51:9385-8. [DOI: 10.1002/anie.201203930] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Indexed: 11/10/2022]
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38
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Lennox AJJ, Lloyd-Jones GC. Organotrifluoroborate Hydrolysis: Boronic Acid Release Mechanism and an Acid–Base Paradox in Cross-Coupling. J Am Chem Soc 2012; 134:7431-41. [DOI: 10.1021/ja300236k] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Guy C. Lloyd-Jones
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol,
BS8 1TS, U.K
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39
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Tan EHP, Lloyd-Jones GC, Harvey JN, Lennox AJJ, Mills BM. [(RCN)2PdCl2]-catalyzed E/Z isomerization of alkenes: a non-hydride binuclear addition-elimination pathway. Angew Chem Int Ed Engl 2011; 50:9602-6. [PMID: 21938759 DOI: 10.1002/anie.201103947] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 07/18/2011] [Indexed: 11/10/2022]
Affiliation(s)
- Emily H P Tan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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40
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Tan EHP, Lloyd-Jones GC, Harvey JN, Lennox AJJ, Mills BM. [(RCN)2PdCl2]-Catalyzed E/Z Isomerization of Alkenes: A Non-Hydride Binuclear Addition-Elimination Pathway. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201103947] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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41
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42
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Butters M, Harvey JN, Jover J, Lennox AJJ, Lloyd-Jones GC, Murray PM. Aryl trifluoroborates in Suzuki-Miyaura coupling: the roles of endogenous aryl boronic acid and fluoride. Angew Chem Int Ed Engl 2010; 49:5156-60. [PMID: 20544767 DOI: 10.1002/anie.201001522] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mike Butters
- AstraZeneca, Severn Road, Hallen, Bristol BS10 7ZE, UK
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