1
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Atkins AP, Dean AC, Lennox AJJ. Benzylic C(sp 3)-H fluorination. Beilstein J Org Chem 2024; 20:1527-1547. [PMID: 39015617 PMCID: PMC11250007 DOI: 10.3762/bjoc.20.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 06/26/2024] [Indexed: 07/18/2024] Open
Abstract
The selective fluorination of C(sp3)-H bonds is an attractive target, particularly for pharmaceutical and agrochemical applications. Consequently, over recent years much attention has been focused on C(sp3)-H fluorination, and several methods that are selective for benzylic C-H bonds have been reported. These protocols operate via several distinct mechanistic pathways and involve a variety of fluorine sources with distinct reactivity profiles. This review aims to give context to these transformations and strategies, highlighting the different tactics to achieve fluorination of benzylic C-H bonds.
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Affiliation(s)
| | - Alice C Dean
- University of Bristol, School of Chemistry, Bristol, BS8 1TS, U.K.
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2
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Willcox DR, Cocco E, Nichol GS, Carlone A, Thomas SP. Catalytic Access to Diastereometrically Pure Four- and Five-Membered Silyl-Heterocycles Using Transborylation. Angew Chem Int Ed Engl 2024; 63:e202401737. [PMID: 38578174 DOI: 10.1002/anie.202401737] [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: 01/24/2024] [Revised: 03/19/2024] [Accepted: 04/03/2024] [Indexed: 04/06/2024]
Abstract
Silyl-heterocycles offer a unique handle to expand and explore chemical space, reactivity, and functionality. The shortage of catalytic methods for the preparation of diverse and functionalized silyl-heterocycles however limits widespread exploration and exploitation. Herein the borane-catalyzed intramolecular 1,1-carboboration of silyl-alkynes has been developed for the synthesis of 2,3-dihydrosilolyl and silylcyclobut-2-enyl boronic esters. Successful, catalytic carboboration has been achieved on a variety of functionally diverse silyl-alkynes, using a borane catalyst and transborylation-enabled turnover. Mechanistic studies, including 13C-labelling, computational studies, and single-turnover experiments, suggest a reaction pathway proceeding by 1,2-hydroboration, 1,1-carboboration, and transborylation to release the alkenyl boronic ester product and regenerate the borane catalyst.
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Affiliation(s)
- Dominic R Willcox
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, United Kingdom
| | - Emanuele Cocco
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, United Kingdom
- Department of Physical and Chemical Sciences, Università degli Studi dell'Aquila, via Vetoio, 67100, L'Aquila, Italy
| | - Gary S Nichol
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, United Kingdom
| | - Armando Carlone
- Department of Physical and Chemical Sciences, Università degli Studi dell'Aquila, via Vetoio, 67100, L'Aquila, Italy
| | - Stephen P Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, United Kingdom
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3
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Lucas Kane D, Figula BC, Balaraman K, Bertke JA, Wolf C. General alkyl fluoride functionalization via short-lived carbocation-organozincate ion pairs. Nat Commun 2024; 15:1866. [PMID: 38424080 PMCID: PMC10904780 DOI: 10.1038/s41467-024-45756-4] [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: 08/31/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024] Open
Abstract
Fluorinated organic compounds are frequently used across the chemical and life sciences. Although a large, structurally diverse pool of alkyl fluorides is nowadays available, synthetic applications trail behind the widely accepted utility of other halides. We envisioned that C(sp2)-C(sp3) cross-coupling reactions of alkyl fluorides with fluorophilic organozinc compounds should be possible through a heterolytic mechanism that involves short-lived ion pairs and uses the stability of the Zn-F bond as the thermodynamic driving force. This would be mechanistically different from previously reported radical reactions and overcome long-standing limitations of organometallic cross-coupling methodology, including competing β-hydride elimination, homodimerization and hydrodefluorination. Here, we show a practical Csp3-F bond functionalization method that expands the currently restricted synthetic space of unactivated primary, secondary and tertiary C(sp3)-F bonds but also uses benzylic, propargylic and acyl fluorides. Many functional groups and sterically demanding substrates are tolerated, which allows practical carbon-carbon bond formation and late-stage functionalization.
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Affiliation(s)
- D Lucas Kane
- Georgetown University, Chemistry Department, Washington, DC, 20057, USA
| | - Bryan C Figula
- Georgetown University, Chemistry Department, Washington, DC, 20057, USA
| | - Kaluvu Balaraman
- Georgetown University, Chemistry Department, Washington, DC, 20057, USA
| | - Jeffery A Bertke
- Georgetown University, Chemistry Department, Washington, DC, 20057, USA
| | - Christian Wolf
- Georgetown University, Chemistry Department, Washington, DC, 20057, USA.
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4
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Chen C, Guo J, Wu C, Duan X, Zhang L. Borate-Functionalized Disiloxane as Effective Electrolyte Additive for 4.5 V LiNi 0.8Co 0.1Mn 0.1O 2/Graphite Batteries. ACS APPLIED MATERIALS & INTERFACES 2024; 16:8733-8741. [PMID: 38345337 DOI: 10.1021/acsami.3c16531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) is considered the most prominent cathode material to establish a practical high energy density of lithium-ion batteries (LIBs) for future electric vehicles. The energy density of LIBs is greatly determined by the capacity of electrode materials and the operating voltage of the cells. To further improve the cycle lifespan of NCM811 batteries to meet the requirement of driving range for the electric vehicle market, it is vital to design a novel electrolyte additive that can enhance the stability of the cathode/electrolyte interface at a wide range of voltage. Herein, a novel borate functionalized disiloxane compound, 1,1,1,3,3-pentamethyl-3-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl) disiloxane (PMBPDS), is synthesized as cathode electrolyte interphase (CEI) film-forming additive to improve the cycling performance of NCM811 batteries. Systematic studies reveal that PMBPDS can construct a stable CEI film on the NCM811 surface and efficiently scavenge hydrofluoric acid (HF). The PMBPDS-derived CEI prevents the dissolution of transmission metals in the NCM811 cathode and enhances the capacity retention of NCM811/graphite cells from 68.3 to 70.6% after 200 cycles at 1 C in the voltage window of 3-4.5 V. This work provides more understanding on designing the molecular structure of additive compounds for improving the electrochemical performance of LIBs.
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Affiliation(s)
- Cheng Chen
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, Guangdong, China
| | - Jiali Guo
- Dongguan Amperex Technology Ltd., Songshan Lake, Dongguan 523808, Guangdong, China
| | - Chunlei Wu
- Hubei Huifu Nanomaterial Co. Ltd., Yichang 443007, Hubei , China
| | - Xianjian Duan
- Hubei Huifu Nanomaterial Co. Ltd., Yichang 443007, Hubei , China
| | - Lingzhi Zhang
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, Guangdong, China
- School of Energy Science and Engineering, University of Science and Technology of China, Hefei 230026, Anhui, China
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5
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Hooker LV, Bandar JS. Synthetic Advantages of Defluorinative C-F Bond Functionalization. Angew Chem Int Ed Engl 2023; 62:e202308880. [PMID: 37607025 PMCID: PMC10843719 DOI: 10.1002/anie.202308880] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/20/2023] [Accepted: 08/21/2023] [Indexed: 08/24/2023]
Abstract
Much progress has been made in the development of methods to both create compounds that contain C-F bonds and to functionalize C-F bonds. As such, C-F bonds are becoming common and versatile synthetic functional handles. This review summarizes the advantages of defluorinative functionalization reactions for small molecule synthesis. The coverage is organized by the type of carbon framework the fluorine is attached to for mono- and polyfluorinated motifs. The main challenges, opportunities and advances of defluorinative functionalization are discussed for each class of organofluorine. Most of the text focuses on case studies that illustrate how defluorofunctionalization can improve routes to synthetic targets or how the properties of C-F bonds enable unique mechanisms and reactions. The broader goal is to showcase the opportunities for incorporating and exploiting C-F bonds in the design of synthetic routes, improvement of specific reactions and advent of new methods.
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Affiliation(s)
- Leidy V Hooker
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jeffrey S Bandar
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
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6
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Iwasaki T, Kambe N. Cross- and Multi-Coupling Reactions Using Monofluoroalkanes. CHEM REC 2023; 23:e202300033. [PMID: 37070641 DOI: 10.1002/tcr.202300033] [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: 01/30/2023] [Revised: 04/03/2023] [Indexed: 04/19/2023]
Abstract
Carbon-fluorine bonds are stable and have demonstrated sluggishness against various chemical manipulations. However, selective transformations of C-F bonds can be achieved by developing appropriate conditions as useful synthetic methods in organic chemistry. This review focuses on C-C bond formation at monofluorinated sp3 -hybridized carbons via C-F bond cleavage, including cross-coupling and multi-component coupling reactions. The C-F bond cleavage mechanisms on the sp3 -hybridized carbon centers can be primarily categorized into three types: Lewis acids promoted F atom elimination to generate carbocation intermediates; nucleophilic substitution with metal or carbon nucleophiles supported by the activation of C-F bonds by coordination of Lewis acids; and the cleavage of C-F bonds via a single electron transfer. The characteristic features of alkyl fluorides, in comparison with other (pseudo)halides as promising electrophilic coupling counterparts, are also discussed.
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Affiliation(s)
- Takanori Iwasaki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Nobuaki Kambe
- Research Center for Environmental Preservation, Osaka University, 2-4 Yamadaoka, Suita, Osaka, 565-0871, Japan
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7
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Mancinelli JP, Kong WY, Guo W, Tantillo DJ, Wilkerson-Hill SM. Borane-Catalyzed C-F Bond Functionalization of gem-Difluorocyclopropenes Enables the Synthesis of Orphaned Cyclopropanes. J Am Chem Soc 2023; 145:17389-17397. [PMID: 37494703 DOI: 10.1021/jacs.3c05278] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Herein, we disclose an approach to synthesize tert-alkyl cyclopropanes by leveraging C-F bond functionalization of gem-difluorocyclopropenes using tris(pentafluorophenyl)borane catalysis. The reaction proceeds through the intermediacy of a fluorocyclopropenium ion, which was confirmed by the isolation of [Ph2(C6D5)C3]+[(C6F5)3BF]-. We found that silylketene acetal nucleophiles were optimal reaction partners with fluorocyclopropenium ion intermediates yielding fully substituted cyclopropenes functionalized with two α-tert-alkyl centers (63-93% yield). The regioselectivity of the addition to cyclopropenium ions is controlled by their steric and electronic properties and enables access to 3,3-bis(difluoromethyl)cyclopropenes in short order. The resulting cyclopropene products are readily reduced to the corresponding orphaned cyclopropanes under hydrogenation conditions. Quantum chemical calculations reveal the nature of the C-F bond cleavage steps and provide evidence for catalysis by boron and not silylated oxonium ions, though Si-F bond formation is the enthalpic driving force for the reaction.
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Affiliation(s)
- Joseph P Mancinelli
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Wang-Yeuk Kong
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Wentao Guo
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Dean J Tantillo
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Sidney M Wilkerson-Hill
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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8
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Willcox DR, Thomas SP. Group 13 exchange and transborylation in catalysis. Beilstein J Org Chem 2023; 19:325-348. [PMID: 36998308 PMCID: PMC10043741 DOI: 10.3762/bjoc.19.28] [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: 12/21/2022] [Accepted: 02/24/2023] [Indexed: 04/01/2023] Open
Abstract
Catalysis is dominated by the use of rare and potentially toxic transition metals. The main group offers a potentially sustainable alternative for catalysis, due to the generally higher abundance and lower toxicity of these elements. Group 13 elements have a rich catalogue of stoichiometric addition reactions to unsaturated bonds but cannot undergo the redox chemistry which underpins transition-metal catalysis. Group 13 exchange reactions transfer one or more groups from one group 13 element to another, through σ-bond metathesis; where boron is both of the group 13 elements, this is termed transborylation. These redox-neutral processes are increasingly being used to render traditionally stoichiometric group 13-mediated processes catalytic and develop new catalytic processes, examples of which are the focus of this review.
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Affiliation(s)
- Dominic R Willcox
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, EH9 3FJ, United Kingdom
| | - Stephen P Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, EH9 3FJ, United Kingdom
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9
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Phatake RS, Averdunk A, Würtele C, Gellrich U. Piers’ Borane-Catalyzed Dimerization of Arylallenes via Transborylation: A Synthetic and Mechanistic Study. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ravindra S. Phatake
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Christian Würtele
- Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
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10
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Thomas SP, Bage AD, Nicholson K, Hunt TA, Langer T. Transborylation-Enabled Boron Catalysis. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/s-0040-1720046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AbstractThis review highlights transborylation (controlled boron-boron exchange) and its applications as a turnover strategy in boron-catalysed methodologies. Catalytic applications of B–C, B–O, B–N, B–F, B–S, and B–Se transborylations are discussed in the context of transborylation-enabled catalysis, across a wide range of organic transformations including hydroboration, C–C bond formation, C–H borylation, chemoselective reduction, and asymmetric reduction.1 Introduction2 B–C Transborylation3 B–O Transborylation4 B–N Transborylation5 B–F Transborylation6 B–S Transborylation7 Conclusion
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Affiliation(s)
| | - Andrew D. Bage
- EaStCHEM School of Chemistry, The University of Edinburgh
| | | | | | - Thomas Langer
- Pharmaceutical Technology & Development, Chemical Development U.K., AstraZeneca
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11
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Balaraman K, Kyriazakos S, Palmer R, Thanzeel FY, Wolf C. Selective Csp 3-F Bond Functionalization with Lithium Iodide. SYNTHESIS-STUTTGART 2022; 54:4320-4328. [PMID: 36330045 PMCID: PMC9624501 DOI: 10.1055/s-0041-1738383] [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] [Indexed: 10/18/2022]
Abstract
A highly efficient method for C-F bond functionalization of a broad variety of activated and unactivated aliphatic substrates with inexpensive lithium iodide is presented. Primary, secondary, tertiary, benzylic, propargylic and α-functionalized alkyl fluorides react in chlorinated or aromatic solvents at room temperature or upon heating to the corresponding iodides which are isolated in 91-99% yield. The reaction is selective for aliphatic monofluorides and can be coupled with in situ nucleophilic iodide replacements to install carbon-carbon, carbon-nitrogen and carbon-sulfur bonds with high yields. Alkyl difluorides, trifluorides, even in activated benzylic positions, are inert under the same conditions and aryl fluoride bonds are also tolerated.
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Affiliation(s)
- Kaluvu Balaraman
- Georgetown University, Chemistry Department, Washington, DC 20057, USA
| | | | - Rachel Palmer
- Georgetown University, Chemistry Department, Washington, DC 20057, USA
| | - F Yushra Thanzeel
- Georgetown University, Chemistry Department, Washington, DC 20057, USA
| | - Christian Wolf
- Georgetown University, Chemistry Department, Washington, DC 20057, USA
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12
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Moreno González A, Nicholson K, Llopis N, Nichol GS, Langer T, Baeza A, Thomas SP. Diastereoselective, Catalytic Access to Cross-Aldol Products Directly from Esters and Lactones. Angew Chem Int Ed Engl 2022; 61:e202209584. [PMID: 35916601 PMCID: PMC9804986 DOI: 10.1002/anie.202209584] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Indexed: 01/09/2023]
Abstract
High oxidation-state carbonyl coupling partners including esters and lactones were reacted with enones to give aldol-type products directly using two-fold organoborane catalysis. This new retrosynthetic disconnection to aldol-type products is compatible with enolisable coupling partners, without self-condensation, and couples the high reactivity of secondary dialkylboranes with the stability of pinacolboronic esters. Excellent chemoselectivity, substrate scope (including those containing reducible functionalities and free alcohols) and diastereocontrol were achieved to access both the syn- and anti-aldol-type products. Mechanistic studies confirmed the two-fold catalytic role of the single secondary borane catalyst for boron enolate formation and formation of an aldehyde surrogate from the ester or lactone coupling partner.
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Affiliation(s)
- Adrián Moreno González
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Kieran Nicholson
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Natalia Llopis
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Gary S. Nichol
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Thomas Langer
- AstraZeneca Pharmaceutical Technology & DevelopmentChemical Development UKSilk RoadMacclesfieldSK10 2NAUK
| | - Alejandro Baeza
- Instituto de Síntesis Orgánica and Dpto. de Química OrgánicaUniversidad de AlicanteApdo. 9903080AlicanteSpain
| | - Stephen P. Thomas
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
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13
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Pradhan S, Sankar RV, Gunanathan C. A Boron-Nitrogen Double Transborylation Strategy for Borane-Catalyzed Hydroboration of Nitriles. J Org Chem 2022; 87:12386-12396. [PMID: 36045008 DOI: 10.1021/acs.joc.2c01655] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Organoborane-catalyzed hydroboration of nitriles provides N,N-diborylamines, which act as efficient synthons for the synthesis of primary amines and secondary amides. Known nitrile hydroboration methods are dominated by metal catalysis. Simple and metal-free hydroboration of nitriles using diborane [H-B-9-BBN]2 as a catalyst and pinacolborane as a turnover reagent is reported. The reaction of monomeric H-B-9-BBN with nitriles leads to the hydrido-bridged diborylimine intermediate; a subsequent sequential double hydroboration-transborylation pathway involving B-N/B-H σ bond metathesis is proposed.
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Affiliation(s)
- Subham Pradhan
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
| | - Raman Vijaya Sankar
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
| | - Chidambaram Gunanathan
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
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14
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Nicholson K, Peng Y, Llopis N, Willcox DR, Nichol GS, Langer T, Baeza A, Thomas SP. Boron-Catalyzed, Diastereo- and Enantioselective Allylation of Ketones with Allenes. ACS Catal 2022; 12:10887-10893. [PMID: 36082052 PMCID: PMC9442582 DOI: 10.1021/acscatal.2c03158] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/11/2022] [Indexed: 01/04/2023]
Affiliation(s)
- Kieran Nicholson
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Yuxuan Peng
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Natalia Llopis
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Dominic R. Willcox
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Gary S. Nichol
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Thomas Langer
- Pharmaceutical Technology & Development, Chemical Development U.K., AstraZeneca, Silk Road, Macclesfield SK10 2NA, United Kingdom
| | - Alejandro Baeza
- Instituto de Síntesis Orgánica and Dpto. de Química Orgánica, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
| | - Stephen P. Thomas
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
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15
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Thomas S, González AM, Nicholson K, Llopis N, Nichol GS, Langer T, Baeza A. Diastereoselective, Catalytic Access to Cross‐aldol Products Directly from Esters and Lactones. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Stephen Thomas
- University of Edinburgh School of Chemistry Joseph Black Building,King's Buildings, West Mains Road EH9 3FJ Edinburgh UNITED KINGDOM
| | | | - Kieran Nicholson
- The University of Edinburgh School of Chemistry School of Chemistry UNITED KINGDOM
| | - Natalia Llopis
- The University of Edinburgh School of Chemistry School of Chemistry UNITED KINGDOM
| | - Gary S. Nichol
- The University of Edinburgh School of Chemistry School of Chemistry UNITED KINGDOM
| | - Thomas Langer
- AstraZeneca UK Ltd Macclesfield Chemical Development UK UNITED KINGDOM
| | - Alejandro Baeza
- Universidad de Alicante: Universitat d'Alacant Dpto. de Química Orgánica SPAIN
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16
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Balaraman K, Wolf C. Chemodivergent Csp 3─F bond functionalization and cross-electrophile alkyl-alkyl coupling with alkyl fluorides. SCIENCE ADVANCES 2022; 8:eabn7819. [PMID: 35622926 PMCID: PMC9140971 DOI: 10.1126/sciadv.abn7819] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The widespread use of fluorinated organic compounds in the health, agrochemical, and materials sciences is sustained by a steadily growing pool of commercially available fine chemicals. The synthetic utility of the increasingly ubiquitous Csp3─F bond, however, remains to be fully exploited, which is often a difficult task because of its paramount stability and chemical inertness. Here, we demonstrate chemodivergent activation of monofluoroalkyl compounds toward either nucleophilic or electrophilic intermediates. This is accomplished under conditions that are compatible with several reaction types and many functional groups, which drastically widens the current scope of organofluorine chemistry and sets the stage for carbon-carbon and carbon-heteroatom bond formations, stereoselective construction of bisoxindole alkaloid scaffolds via in situ Umpolung, and cross-electrophilic coupling methodology. The selective generation of either nucleophilic or electrophilic species and the possibility of doing so simultaneously or, alternatively, switching molecular polarity enable previously unidentified synthetic opportunities that recognize alkyl fluorides as chemodivergent building blocks.
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17
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McKnight J, Shavnya A, Sach NW, Blakemore DC, Moses IB, Willis MC. Reductant‐Free Cross‐Electrophile Synthesis of Di(hetero)arylmethanes by Palladium‐Catalyzed Desulfinative C−C Coupling. Angew Chem Int Ed Engl 2022; 61:e202116775. [PMID: 35229419 PMCID: PMC9314995 DOI: 10.1002/anie.202116775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Indexed: 01/13/2023]
Abstract
An efficient Pd‐catalyzed one‐pot desulfinative cross‐coupling to access medicinally relevant di(hetero)arylmethanes is reported. The method is reductant‐free, and involves a sulfinate transfer reagent and a Pd‐catalyst mediating the union of two electrophilic coupling partners; a (hetero)aryl halide and a benzyl halide. We establish for the first time that benzyl sulfinates, generated in situ, undergo efficient Pd‐catalyzed desulfinative cross‐coupling with (hetero)aryl halides to generate di(hetero)arylmethanes. The reaction can be extended to benzylic pseudohalides derived from benzyl alcohols. The reactions are straightforward to perform and scalable, and all reaction components are commercially available.
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Affiliation(s)
- Janette McKnight
- Department of Chemistry University of Oxford Chemistry Research Laboratory 12 Mansfield Road Oxford OX1 3TA UK
| | - Andre Shavnya
- Medicine Design, Pfizer Inc. Eastern Point Road Groton CT 06340 USA
| | - Neal W. Sach
- Medicine Design, La Jolla Laboratories, Pfizer Inc. 10770 Science Center Drive San Diego CA 92121 USA
| | | | - Ian B. Moses
- Chemical Research and Development, Pfizer Ltd. Discovery Park, Ramsgate Rd Sandwich CT13 9ND UK
| | - Michael C. Willis
- Department of Chemistry University of Oxford Chemistry Research Laboratory 12 Mansfield Road Oxford OX1 3TA UK
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18
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McKnight J, Shavnya A, Sach NW, Blakemore DC, Moses IB, Willis MC. Reductant‐Free Cross‐Electrophile Synthesis of Di(hetero)arylmethanes by Palladium‐Catalyzed Desulfinative C−C Coupling. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202116775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Janette McKnight
- Department of Chemistry University of Oxford Chemistry Research Laboratory 12 Mansfield Road Oxford OX1 3TA UK
| | - Andre Shavnya
- Medicine Design, Pfizer Inc. Eastern Point Road Groton CT 06340 USA
| | - Neal W. Sach
- Medicine Design, La Jolla Laboratories, Pfizer Inc. 10770 Science Center Drive San Diego CA 92121 USA
| | | | - Ian B. Moses
- Chemical Research and Development, Pfizer Ltd. Discovery Park, Ramsgate Rd Sandwich CT13 9ND UK
| | - Michael C. Willis
- Department of Chemistry University of Oxford Chemistry Research Laboratory 12 Mansfield Road Oxford OX1 3TA UK
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19
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Covalently tethering disulfonic acid moieties onto polyoxometalate boosts acid strength and catalytic performance for hydroxyalkylation/alkylation reaction. Sci China Chem 2022. [DOI: 10.1007/s11426-021-1181-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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20
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Zheng H, Xiong H, Su C, Cao H, Yao H, Liu X. Photoinduced successive oxidative ring-opening and borylation of indolizines with NHC–boranes. RSC Adv 2022; 12:470-474. [PMID: 35424515 PMCID: PMC8978647 DOI: 10.1039/d1ra08072e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/14/2021] [Indexed: 11/21/2022] Open
Abstract
A facile photoinduced successive oxidative ring-opening and borylation of indolizines with NHC–boranes via a one-pot method has been unveiled. This photo-promoted strategy enables the formation of unsaturated NHC–boryl carboxylates under transition metal-free and radical initiator-free conditions. A wide array of pyridine-containing NHC–boryl carboxylates were directly prepared in moderate to good yields. This work contributes to a better understanding of the reactivity and photo-behavior of both indolizines and NHC–boranes. A facile photoinduced successive oxidative ring-opening and borylation of indolizines with NHC–boranes via a one-pot method has been unveiled. This photo-promoted strategy enables the formation of unsaturated NHC–boryl carboxylates under transition metal-free conditions.![]()
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Affiliation(s)
- Huitao Zheng
- School of Chemistry and Chemical Engineering and Guangdong Cosmetics Engineering & Technology Research Center, Guangdong Pharmaceutical University, Zhongshan 528458, China
| | - Honggang Xiong
- School of Chemistry and Chemical Engineering and Guangdong Cosmetics Engineering & Technology Research Center, Guangdong Pharmaceutical University, Zhongshan 528458, China
| | - Chaobo Su
- School of Chemistry and Chemical Engineering and Guangdong Cosmetics Engineering & Technology Research Center, Guangdong Pharmaceutical University, Zhongshan 528458, China
| | - Hua Cao
- School of Chemistry and Chemical Engineering and Guangdong Cosmetics Engineering & Technology Research Center, Guangdong Pharmaceutical University, Zhongshan 528458, China
| | - Huagang Yao
- School of Chemistry and Chemical Engineering and Guangdong Cosmetics Engineering & Technology Research Center, Guangdong Pharmaceutical University, Zhongshan 528458, China
| | - Xiang Liu
- School of Chemistry and Chemical Engineering and Guangdong Cosmetics Engineering & Technology Research Center, Guangdong Pharmaceutical University, Zhongshan 528458, China
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21
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Kirschner S, Peters M, Yuan K, Uzelac M, Ingleson MJ. Developing organoboranes as phase transfer catalysts for nucleophilic fluorination using CsF. Chem Sci 2022; 13:2661-2668. [PMID: 35340859 PMCID: PMC8890113 DOI: 10.1039/d2sc00303a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/09/2022] [Indexed: 12/05/2022] Open
Abstract
Despite the general high fluorophilicity of boron, organoboranes such as BEt3 and 3,5-(CF3)2C6H3–BPin are shown herein for the first time, to our knowledge, to be effective (solid to solution) phase-transfer catalysts for the fluorination of certain organohalides with CsF. Significant (up to 30% e.e.) chiral induction during nucleophilic fluorination to form β-fluoroamines using oxazaborolidine (pre)catalysts and CsF also can be achieved. Screening different boranes revealed a correlation between calculated fluoride affinity of the borane and nucleophilic fluorination reactivity, with sufficient fluoride affinity required for boranes to react with CsF and form Cs[fluoroborate] salts, but too high a fluoride affinity leading to fluoroborates that are poor at transferring fluoride to an electrophile. Fluoride affinity is only one component controlling reactivity in this context; effective fluorination also is dependent on the ligation of Cs+ which effects both the phase transfer of CsF and the magnitude of the [Cs⋯F-BR3] interaction and thus the B–F bond strength. Effective ligation of Cs+ (e.g. by [2.2.2]-cryptand) facilitates phase transfer of CsF by the borane but also weakens the Cs⋯F–B interaction which in turn strengthens the B–F bond – thus disfavouring fluoride transfer to an electrophile. Combined, these findings indicate that optimal borane mediated fluorination occurs using robust (to the fluorination conditions) boranes with fluoride affinity of ca. 105 kJ mol−1 (relative to Me3Si+) under conditions where a signficant Cs⋯F–B interaction persists. Simple boranes with the optimal fluoride ion affinity are effective as catalysts for phase transfer nucleophilic fluorination with CsF.![]()
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Affiliation(s)
- Sven Kirschner
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Matthew Peters
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Kang Yuan
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Marina Uzelac
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Michael J Ingleson
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
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22
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Abstract
In the last two decades, boron-based catalysis has been gaining increasing traction in the field of organic synthesis. The use of halogenated triarylboranes as main group Lewis acid catalysts is an attractive strategy. It has been applied in a growing number of transformations over the years, where they may perform comparably or even better than the gold standard catalysts. This review discusses methods of borane synthesis and cutting-edge boron-based Lewis acid catalysis, focusing especially on tris(pentafluorophenyl)-borane [B(C6F5)3], and other halogenated triarylboranes, highlighting how boron Lewis acids employed as catalysts can unlock a plethora of unprecedented chemical transformations or improve the efficiency of existing reactions.
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23
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Balaraman K, Wolf C. Palladium and Nickel Catalyzed Suzuki Cross-Coupling with Alkyl Fluorides. Org Lett 2021; 23:8994-8999. [PMID: 34723542 DOI: 10.1021/acs.orglett.1c03515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Suzuki cross-coupling of benzylic and unactivated aliphatic fluorides with aryl- and alkenylboronic acids has been achieved via mechanistically distinct Pd and Ni catalyzed pathways that outperform competing protodeboronation, β-hydride elimination, and homocoupling processes. The utility is demonstrated with more than 20 examples including heterocyclic structures, 1,1-disubstituted and trans-1,2-disubstituted alkenes, and by the incorporation of acetonitrile into functionalized (hetero)arenes.
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Affiliation(s)
- Kaluvu Balaraman
- Georgetown University, Chemistry Department, Washington, District of Columbia 20057, United States
| | - Christian Wolf
- Georgetown University, Chemistry Department, Washington, District of Columbia 20057, United States
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24
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Benn K, Nicholson K, Langer T, Thomas SP. A boron-nitrogen transborylation enabled, borane-catalysed reductive cyanation of enones. Chem Commun (Camb) 2021; 57:9406-9409. [PMID: 34528968 DOI: 10.1039/d1cc03649a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyanation offers a simple method for the introduction of a nitrile group into organic molecules and an orthogonal route for the installation of a wide array of functional groups using simple transformations. Cyanation methods are dominated by transition metal catalysis and the use of hydrogen cyanide gas. Here, the electrophilic cyanation of enones was achieved using a main-group catalyst and a non-toxic, electrophilic cyanide source. This protocol was applied across a broad substrate scope including those containing reducible functional groups. Mechanistic studies indicated an amino-borane intermediate which underwent B-N transborylation (B-N/B-H exchange) to achieve catalytic turnover.
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Affiliation(s)
- Kieran Benn
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK.
| | - Kieran Nicholson
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK.
| | - Thomas Langer
- Pharmaceutical Technology & Development, Chemicals Development U.K., AstraZeneca, Macclesfield SK10 2NA, UK
| | - Stephen P Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK.
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25
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He T, Klare HFT, Oestreich M. Silylium-Ion Regeneration by Protodesilylation Enables Friedel–Crafts Alkylation with Less Isomerization and No Defunctionalization. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03602] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tao He
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Hendrik F. T. Klare
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
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26
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Lyu H, Kevlishvili I, Yu X, Liu P, Dong G. Boron insertion into alkyl ether bonds via zinc/nickel tandem catalysis. Science 2021; 372:175-182. [PMID: 33833121 DOI: 10.1126/science.abg5526] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 03/05/2021] [Indexed: 12/23/2022]
Abstract
Mild methods to cleave the carbon-oxygen (C-O) bond in alkyl ethers could simplify chemical syntheses through the elaboration of these robust, readily available precursors. Here we report that dibromoboranes react with alkyl ethers in the presence of a nickel catalyst and zinc reductant to insert boron into the C-O bond. Subsequent reactivity can effect oxygen-to-nitrogen substitution or one-carbon homologation of cyclic ethers and more broadly streamline preparation of bioactive compounds. Mechanistic studies reveal a cleavage-then-rebound pathway via zinc/nickel tandem catalysis.
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Affiliation(s)
- Hairong Lyu
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Ilia Kevlishvili
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Xuan Yu
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Guangbin Dong
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA.
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