1
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Lai J, Xiao X, Shao S, Wang S, Kan J, Su W. Photoinduced Transition-Metal and External Photosensitizer Free Benzylic Fluorination of Unactivated Alkylarenes. Chemistry 2024; 30:e202401669. [PMID: 38970448 DOI: 10.1002/chem.202401669] [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: 04/28/2024] [Revised: 06/20/2024] [Accepted: 07/05/2024] [Indexed: 07/08/2024]
Abstract
A green and efficient protocol for the direct monofluorination of unactivated alkylarenes under visible-light irradiation has been developed, without any extraneous transition-metal catalysts or photosensitizers. This method is compatible with a broad spectrum of functional groups, including carboxylic and alcoholic scaffolds, under mild reaction conditions. Gram-scale synthesis of a fluorine-containing pharmaceutical analogue was successfully executed, underscoring the strategy's reliability and practicality. Furthermore, mechanistic studies suggest that a single-electron transfer mechanism might be responsible for the generation of the benzylic radicals in initiation step.
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Affiliation(s)
- Jiawen Lai
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Xuan Xiao
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Shixing Shao
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Shuping Wang
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Jian Kan
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Weiping Su
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, 350108, Fuzhou Fujian, P. R. China
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2
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Kraemer Y, Buldt JA, Kong WY, Stephens AM, Ragan AN, Park S, Haidar ZC, Patel AH, Shey R, Dagan R, McLoughlin CP, Fettinger JC, Tantillo DJ, Pitts CR. Overcoming a Radical Polarity Mismatch in Strain-Release Pentafluorosulfanylation of [1.1.0]Bicyclobutanes: An Entryway to Sulfone- and Carbonyl-Containing SF 5-Cyclobutanes. Angew Chem Int Ed Engl 2024; 63:e202319930. [PMID: 38237059 PMCID: PMC11045327 DOI: 10.1002/anie.202319930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Indexed: 04/26/2024]
Abstract
The first assortment of achiral pentafluorosulfanylated cyclobutanes (SF5-CBs) are now synthetically accessible through strain-release functionalization of [1.1.0]bicyclobutanes (BCBs) using SF5Cl. Methods for both chloropentafluorosulfanylation and hydropentafluorosulfanylation of sulfone-based BCBs are detailed herein, as well as proof-of-concept that the logic extends to tetrafluoro(aryl)sulfanylation, tetrafluoro(trifluoromethyl)sulfanylation, and three-component pentafluorosulfanylation reactions. The methods presented enable isolation of both syn and anti isomers of SF5-CBs, but we also demonstrate that this innate selectivity can be overridden in chloropentafluorosulfanylation; that is, an anti-stereoselective variant of SF5Cl addition across sulfone-based BCBs can be achieved by using inexpensive copper salt additives. Considering the SF5 group and CBs have been employed individually as nonclassical bioisosteres, structural aspects of these unique SF5-CB "hybrid isosteres" were then contextualized using SC-XRD. From a mechanistic standpoint, chloropentafluorosulfanylation ostensibly proceeds through a curious polarity mismatch addition of electrophilic SF5 radicals to the electrophilic sites of the BCBs. Upon examining carbonyl-containing BCBs, we also observed rare instances whereby radical addition to the 1-position of a BCB occurs. The nature of the key C(sp3)-SF5 bond formation step - among other mechanistic features of the methods we disclose - was investigated experimentally and with DFT calculations. Lastly, we demonstrate compatibility of SF5-CBs with various downstream functionalizations.
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Affiliation(s)
- Yannick Kraemer
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Jón Atiba Buldt
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Wang-Yeuk Kong
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Alexander M Stephens
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Abbey N Ragan
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Soojun Park
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Zane C Haidar
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Ansh Hiten Patel
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Rachel Shey
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Roee Dagan
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Connor P McLoughlin
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - James C Fettinger
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Dean J Tantillo
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Cody Ross Pitts
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA
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3
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Joven-Sancho D, Echeverri A, Saffon-Merceron N, Contreras-García J, Nebra N. An Organocopper(III) Fluoride Triggering C-CF 3 Bond Formation. Angew Chem Int Ed Engl 2024; 63:e202319412. [PMID: 38147576 DOI: 10.1002/anie.202319412] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 12/22/2023] [Accepted: 12/22/2023] [Indexed: 12/28/2023]
Abstract
Copper(III) fluorides are catalytically competent, yet elusive, intermediates in cross-coupling. The synthesis of [PPh4 ][CuIII (CF3 )3 F] (2), the first stable (isolable) CuIII -F, was accomplished via chloride addition to [CuIII (CF3 )3 (py)] (1) yielding [PPh4 ][CuIII (CF3 )3 Cl(py)] (1⋅Cl), followed by treatment with AgF. The CuIII halides 1⋅Cl and 2 were fully characterized using nuclear magnetic resonance (NMR) spectroscopy, single crystal X-ray diffraction (Sc-XRD) and elemental analysis (EA). Complex 2 proved capable of forging C-CF3 bonds from silyl-capped alkynes. In-depth mechanistic studies combining probes, theoretical calculations, trapping of intermediate 4a ([PPh4 ][CuIII (CF3 )3 (C≡CPh)]) and radical tests unveil the key role of the CuIII acetylides that undergo facile 2e- reductive elimination furnishing the trifluoromethylated alkynes (RC≡CCF3 ), which are industrially relevant synthons in drug discovery, pharma and agrochemistry.
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Affiliation(s)
- Daniel Joven-Sancho
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Andrea Echeverri
- Laboratoire de Chimie Théorique (LCT), Sorbonne Université, CNRS, 4, Place Jussieu, 75005, Paris, France
| | - Nathalie Saffon-Merceron
- Institut de Chimie de Toulouse ICT-UAR2599, Université Paul Sabatier, CNRS, 31062, Toulouse Cedex, France
| | - Julia Contreras-García
- Laboratoire de Chimie Théorique (LCT), Sorbonne Université, CNRS, 4, Place Jussieu, 75005, Paris, France
| | - Noel Nebra
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
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4
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Alvarez EM, Stewart G, Ullah M, Lalisse R, Gutierrez O, Malapit CA. Site-Selective Electrochemical Arene C-H Amination. J Am Chem Soc 2024; 146:3591-3597. [PMID: 38295054 PMCID: PMC11071122 DOI: 10.1021/jacs.3c11506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Here we present the discovery and development of a highly selective aromatic C-H amination reaction. This electrochemical strategy involves a cathodic reduction process that generates highly electrophilic dicationic N-centered radicals that can efficiently engage in aromatic C-H functionalization and channel the regioselectivity of the aromatic substitution. The nitrogen-radical cation-pi interaction with arenes used throughout nature leads to a charge transfer mechanism, with subsequent aromatic C-N bond formation. This electrochemical process generates aryl DABCOnium salts in excellent yields and regioselectivities (single regioisomer in most cases). The scope of the reaction on arene is broad where various functionalities such as aryl halides (bromides, chlorides, fluorides), carbonyls (ketones, esters, imides), sulfonamides, and heteroarenes (pyridines, bipyridines, and terpyridines) are well tolerated. Moreover, we disclose the synthetic utility of the aryl DABCOnium salt adducts leading to the direct access of diverse aryl piperazines and the chemoselective cleavage of the exocyclic aryl C(sp2)-N bond over electrophilic C(sp3)-N+ bonds via photoredox catalysis to afford synthetically useful aryl radicals that can engage in aryl C-C and C-P bond formation.
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Affiliation(s)
- Eva Maria Alvarez
- Department of Chemistry, Northwestern University, Technological Institute, Evanston, Illinois 60208, United States
| | - Griffin Stewart
- Department of Chemistry, Northwestern University, Technological Institute, Evanston, Illinois 60208, United States
| | - Mohammed Ullah
- Department of Chemistry, Northwestern University, Technological Institute, Evanston, Illinois 60208, United States
| | - Remy Lalisse
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Osvaldo Gutierrez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Christian A Malapit
- Department of Chemistry, Northwestern University, Technological Institute, Evanston, Illinois 60208, United States
- Center for Catalysis and Surface Science, Northwestern University, Evanston, Illinois 60208, United States
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5
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Nobile E, Doche F, Castanheiro T, Musaev DG, Besset T. Copper-Catalyzed C-H (Phenylsulfonyl)difluoromethylation of Acrylamides: Scope, Mechanism, and Critical Role of Additives. Chemistry 2024; 30:e202303362. [PMID: 38095511 DOI: 10.1002/chem.202303362] [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: 11/15/2023] [Indexed: 02/09/2024]
Abstract
Herein, we report the Cu-complex catalyzed, native functional group-assisted, and TFA/NMF additives promoted (phenylsulfonyl)difluoromethylation of vinylic C(sp2 )-H bond of acrylamides. Using our in-home designed reagent, this reaction enables the construction of the C(sp2 )-CF2 SO2 Ph bond from simple C-H bond activation by copper catalysis under mild reaction conditions with total Z-selectivity. The versatility of utilized fluorinated group was illustrated by its conversion into value-added CF2 moieties as well as the remarkable =CHF residue. The performed experimental and computational mechanistic studies enabled to identify the true nature of active catalyst and substrate, as well as establish critical roles of TFA and NMF additives. In this reaction, the TFA acts as a promoter of the much-needed CuII /CuII →CuIII /CuI disproportionation, while the NMF facilitates the following ligand exchange and C-C coupling processes. We ruled out the generation of radical intermediates and established the C-H activation to be irreversible and the rate-determining step of the entire process.
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Affiliation(s)
- Enzo Nobile
- INSA Rouen Normandie, Univ Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000, Rouen, France
| | - Floriane Doche
- INSA Rouen Normandie, Univ Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000, Rouen, France
| | - Thomas Castanheiro
- INSA Rouen Normandie, Univ Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000, Rouen, France
| | - Djamaladdin G Musaev
- Cherry L. Emerson Center for Scientific Computation, Department of Chemistry, Emory University, 30322, Atlanta, Georgia, United States
| | - Tatiana Besset
- INSA Rouen Normandie, Univ Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000, Rouen, France
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6
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Mandal M, Buss JA, Chen SJ, Cramer CJ, Stahl SS. Mechanistic insights into radical formation and functionalization in copper/ N-fluorobenzenesulfonimide radical-relay reactions. Chem Sci 2024; 15:1364-1373. [PMID: 38274066 PMCID: PMC10806759 DOI: 10.1039/d3sc03597b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 12/09/2023] [Indexed: 01/27/2024] Open
Abstract
Copper-catalysed radical-relay reactions that employ N-fluorobenzenesulfonimide (NFSI) as the oxidant have emerged as highly effective methods for C(sp3)-H functionalization. Herein, computational studies are paired with experimental data to investigate a series of key mechanistic features of these reactions, with a focus on issues related to site-selectivity, enantioselectivity, and C-H substrate scope. (1) The full reaction energetics of enantioselective benzylic C-H cyanation are probed, and an adduct between Cu and the N-sulfonimidyl radical (˙NSI) is implicated as the species that promotes hydrogen-atom transfer (HAT) from the C-H substrate. (2) Benzylic versus 3° C-H site-selectivity is compared with different HAT reagents: Cu/˙NSI, ˙OtBu, and Cl˙, and the data provide insights into the high selectivity for benzylic C-H bonds in Cu/NFSI-catalyzed C-H functionalization reactions. (3) The energetics of three radical functionalization pathways are compared, including radical-polar crossover (RPC) to generate a carbocation intermediate, reductive elimination from a formal CuIII organometallic complex, and radical addition to a Cu-bound ligand. The preferred mechanism is shown to depend on the ligands bound to copper. (4) Finally, the energetics of three different pathways that convert benzylic C-H bonds into benzylic cations are compared, including HAT/ET (ET = electron transfer), relevant to the RPC mechanism with Cu/NFSI; hydride transfer, involved in reactions with high-potential quinones; and sequential ET/PT/ET (PT = proton transfer), involved in catalytic photoredox reactions. Collectively, the results provide mechanistic insights that establish a foundation for further advances in radical-relay C-H functionalization reactions.
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Affiliation(s)
- Mukunda Mandal
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota 207 Pleasant Street SE Minneapolis MN 55455 USA
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Joshua A Buss
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Si-Jie Chen
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Christopher J Cramer
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota 207 Pleasant Street SE Minneapolis MN 55455 USA
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
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7
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Galeotti M, Lee W, Sisti S, Casciotti M, Salamone M, Houk KN, Bietti M. Radical and Cationic Pathways in C( sp3)-H Bond Oxygenation by Dioxiranes of Bicyclic and Spirocyclic Hydrocarbons Bearing Cyclopropane Moieties. J Am Chem Soc 2023; 145:24021-24034. [PMID: 37874906 PMCID: PMC10636757 DOI: 10.1021/jacs.3c07163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/26/2023]
Abstract
A product and DFT computational study on the reactions of 3-ethyl-3-(trifluoromethyl)dioxirane (ETFDO) with bicyclic and spirocyclic hydrocarbons bearing cyclopropyl groups was carried out. With bicyclo[n.1.0]alkanes (n = 3-6), diastereoselective formation of the alcohol product derived from C2-H bond hydroxylation was observed, accompanied by smaller amounts of products derived from oxygenation at other sites. With 1-methylbicyclo[4.1.0]heptane, rearranged products were also observed in addition to the unrearranged products deriving from oxygenation at the most activated C2-H and C5-H bonds. With spiro[2.5]octane and 6-tert-butylspiro[2.5]octane, reaction with ETFDO occurred predominantly or exclusively at the axial C4-H to give unrearranged oxygenation products, accompanied by smaller amounts of rearranged bicyclo[4.2.0]octan-1-ols. The good to outstanding site-selectivities and diastereoselectivities are paralleled by the calculated activation free energies for the corresponding reaction pathways. Computations show that the σ* orbitals of the bicyclo[n.1.0]alkane cis or trans C2-H bonds and spiro[2.5]octanes axial C4-H bond hyperconjugatively interact with the Walsh orbitals of the cyclopropane ring, activating these bonds toward HAT to ETFDO. The detection of rearranged oxygenation products in the oxidation of 1-methylbicyclo[4.1.0]heptane, spiro[2.5]octane, and 6-tert-butylspiro[2.5]octane provides unambiguous evidence for the involvement of cationic intermediates in these reactions, representing the first examples on the operation of ET pathways in dioxirane-mediated C(sp3)-H bond oxygenations. Computations support these findings, showing that formation of cationic intermediates is associated with specific stabilizing hyperconjugative interactions between the incipient carbon radical and the cyclopropane C-C bonding orbitals that trigger ET to the incipient dioxirane derived 1,1,1-trifluoro-2-hydroxy-2-butoxyl radical.
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Affiliation(s)
- Marco Galeotti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica 1, I-00133, Rome, Italy
- QBIS
Research Group, Institut de Química Computacional i Catàlisi
(IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Woojin Lee
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California 90095, United States
| | - Sergio Sisti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica 1, I-00133, Rome, Italy
| | - Martina Casciotti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica 1, I-00133, Rome, Italy
| | - Michela Salamone
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica 1, I-00133, Rome, Italy
| | - K. N. Houk
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California 90095, United States
| | - Massimo Bietti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica 1, I-00133, Rome, Italy
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8
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Wang M, Rowshanpour R, Guan L, Ruskin J, Nguyen PM, Wang Y, Zhang QA, Liu R, Ling B, Woltornist R, Stephens AM, Prasad A, Dudding T, Lectka T, Pitts CR. Competition between C-C and C-H Bond Fluorination: A Continuum of Electron Transfer and Hydrogen Atom Transfer Mechanisms. J Am Chem Soc 2023; 145:22442-22455. [PMID: 37791901 DOI: 10.1021/jacs.3c06477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
In 2015, we reported a photochemical method for directed C-C bond cleavage/radical fluorination of relatively unstrained cyclic acetals using Selectfluor and catalytic 9-fluorenone. Herein, we provide a detailed mechanistic study of this reaction, during which it was discovered that the key electron transfer step proceeds through substrate oxidation from a Selectfluor-derived N-centered radical intermediate (rather than through initially suspected photoinduced electron transfer). This finding led to proof of concept for two new methodologies, demonstrating that unstrained C-C bond fluorination can also be achieved under chemical and electrochemical conditions. Moreover, as C-C and C-H bond fluorination reactions are both theoretically possible on 2-aryl-cycloalkanone acetals and would involve the same reactive intermediate, we studied the competition between single-electron transfer (SET) and apparent hydrogen-atom transfer (HAT) pathways in acetal fluorination reactions using density functional theory. Finally, these analyses were applied more broadly to other classes of C-H and C-C bond fluorination reactions developed over the past decade, addressing the feasibility of SET processes masquerading as HAT in C-H fluorination literature.
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Affiliation(s)
- Muyuan Wang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Rozhin Rowshanpour
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way St. Catharines, Ontario L2S 3A1, Canada
| | - Liangyu Guan
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen 51832, China
| | - Jonah Ruskin
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Phuong Minh Nguyen
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Yuang Wang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Qinze Arthur Zhang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Ran Liu
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Bill Ling
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Ryan Woltornist
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Alexander M Stephens
- Department of Chemistry, University of California Davis, 1 Shields Avenue, Davis, California 95616, United States
| | - Aarush Prasad
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way St. Catharines, Ontario L2S 3A1, Canada
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Cody Ross Pitts
- Department of Chemistry, University of California Davis, 1 Shields Avenue, Davis, California 95616, United States
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9
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Wang X, Zhang X, Xue L, Wang Q, You F, Dai L, Wu J, Kramer S, Lian Z. Mechanochemical Synthesis of Aryl Fluorides by Using Ball Milling and a Piezoelectric Material as the Redox Catalyst. Angew Chem Int Ed Engl 2023; 62:e202307054. [PMID: 37523257 DOI: 10.1002/anie.202307054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/02/2023]
Abstract
Aryl fluorides are important structural motifs in many pharmaceuticals. Although the Balz-Schiemann reaction provides an entry to aryl fluorides from aryldiazonium tetrafluoroborates, it suffers from drawbacks such as long reaction time, high temperature, toxic solvent, toxic gas release, and low functional group tolerance. Here, we describe a general method for the synthesis of aryl fluorides from aryldiazonium tetrafluoroborates using a piezoelectric material as redox catalyst under ball milling conditions in the presence of Selectfluor. This approach effectively addresses the aforementioned limitations. Furthermore, the piezoelectric material can be recycled multiple times. Mechanistic investigations indicate that this fluorination reaction may proceed via a radical pathway, and Selectfluor plays a dual role as both a source of fluorine and a terminal reductant.
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Affiliation(s)
- Xiaohong Wang
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Xuemei Zhang
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Li Xue
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Qingqing Wang
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Fengzhi You
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Lunzhi Dai
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Jiagang Wu
- Department of Materials Science, Sichuan University, 610064, Chengdu, China
| | - Søren Kramer
- Department of Chemistry, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Zhong Lian
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
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10
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Ajitha M, Haines BE, Musaev DG. Mechanism and Selectivity of Copper-Catalyzed Bromination of Distal C(sp 3)-H Bonds. Organometallics 2023; 42:2467-2476. [PMID: 37772274 PMCID: PMC10526628 DOI: 10.1021/acs.organomet.2c00554] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Indexed: 02/25/2023]
Abstract
Unactivated C(sp3)-H bonds are the most challenging substrate class for transition metal-catalyzed C-H halogenation. Recently, the Yu group [Liu, T.; Myers, M. C.; Yu, J. Q. Angew. Chem., Int. Ed.2017, 56 (1), 306-309] has demonstrated that a CuII/phenanthroline catalyst and BrN3, generated in situ from NBS and TMSN3 precursors, can achieve selective C-H bromination distal to a directing group. The current understanding of the mechanism of this reaction has left numerous questions unanswered. Here, we investigated the mechanism of Cu-catalyzed C(sp3)-H bromination with distal site selectivity using density functional theory calculations. We found that this reaction starts with the Br-atom transfer from BrN3 to the Cu center that occurs via a small energy barrier at the singlet-triplet state seam of crossing. In the course of this reaction, the presence of the N-H bond in the substrate is critically important and acts as a directing group for enhancing the stability of the catalyst-substrate interaction and for the recruitment of the substrate to the catalyst. The required C-centered radical substrate formation occurs via direct C-H dehydrogenation by the Cu-coordinated N3 radical, rather than via the previously proposed N-H bond dehydrogenation and then the 1,5-H transfer from the γ-(C-H) bond to the N-radical center pathway. The C-H bond activation by the azide radical is a regioselectivity-controlling step. The following bromination of the C-centered radical by the Cu-coordinated bromine completes the product formation. This reaction step is the rate-limiting step, occurs at the singlet-to-triplet state seam of the crossing point, and is exergonic.
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Affiliation(s)
- Manjaly
J. Ajitha
- Cherry L. Emerson Center for Scientific
Computation, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | | | - Djamaladdin G. Musaev
- Cherry L. Emerson Center for Scientific
Computation, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
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11
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Meger FS, Murphy JA. Recent Advances in C-H Functionalisation through Indirect Hydrogen Atom Transfer. Molecules 2023; 28:6127. [PMID: 37630379 PMCID: PMC10459052 DOI: 10.3390/molecules28166127] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
The functionalisation of C-H bonds has been an enormous achievement in synthetic methodology, enabling new retrosynthetic disconnections and affording simple synthetic equivalents for synthons. Hydrogen atom transfer (HAT) is a key method for forming alkyl radicals from C-H substrates. Classic reactions, including the Barton nitrite ester reaction and Hofmann-Löffler-Freytag reaction, among others, provided early examples of HAT. However, recent developments in photoredox catalysis and electrochemistry have made HAT a powerful synthetic tool capable of introducing a wide range of functional groups into C-H bonds. Moreover, greater mechanistic insights into HAT have stimulated the development of increasingly site-selective protocols. Site-selectivity can be achieved through the tuning of electron density at certain C-H bonds using additives, a judicious choice of HAT reagent, and a solvent system. Herein, we describe the latest methods for functionalizing C-H/Si-H/Ge-H bonds using indirect HAT between 2018-2023, as well as a critical discussion of new HAT reagents, mechanistic aspects, substrate scopes, and background contexts of the protocols.
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Affiliation(s)
- Filip S. Meger
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, 16 Avinguda dels Països Catalans, 43007 Tarragona, Catalonia, Spain
| | - John A. Murphy
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UK
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12
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Yang S, Wu JY, Lin S, Pu M, Huang ZS, Wang H, Li Q. Divergent Fluorinations of Vinylcyclopropanes: Ring-Opening 1,5-Hydrofluorination and Ring-Retaining 1,2-Difluorination. Chem Asian J 2023; 18:e202300476. [PMID: 37366264 DOI: 10.1002/asia.202300476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 06/28/2023]
Abstract
Organofluorine compounds have been widely used in pharmaceutical, agrochemical, and material sciences. Reported herein are divergent fluorination reactions of vinylcyclopropanes with different electrophiles, which allow the facile synthesis of homoallylic monofluorides and vicinal-difluorides through ring-opening 1,5-hydrofluorination and ring-retaining 1,2-difluorination, respectively. Both protocols feature mild conditions, simple operations, good functional group tolerance, and generally good yields. The practicality of these reactions is demonstrated by their scalability, as well as the successful conversion of the formed homoallylic monofluorides into other complex fluorinated molecules.
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Affiliation(s)
- Shuang Yang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, P. R. China
| | - Jun-Yunzi Wu
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, P. R. China
| | - Shuang Lin
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, P. R. China
| | - Meicen Pu
- Department of Endocrinology and Metabolism, Nanfang Hospital of Southern Medical University, Guangzhou, 510515, P. R. China
| | - Zhi-Shu Huang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, P. R. China
| | - Honggen Wang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, P. R. China
| | - Qingjiang Li
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, P. R. China
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13
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Joshi H, Paul D, Sathyamoorthi S. Oxidations of Alcohols, Aldehydes, and Diols Using NaBr and Selectfluor. J Org Chem 2023; 88:11240-11252. [PMID: 37490704 PMCID: PMC10804234 DOI: 10.1021/acs.joc.3c01307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
We present protocols for the oxidation of alcohols and aldehydes and for the oxidative cyclization of diols which use a combination of Selectfluor and NaBr. For most substrates, the optimal solvent system is a 1:1 mixture of CH3CN/H2O, but, in select cases, biphasic 1:1 mixtures of EtOAc/H2O or CH2Cl2/H2O are superior. This procedure is operationally simple, uses inexpensive and readily available reagents, and tolerates a variety of functional groups. Mechanistic studies suggest that the active oxidant is hypobromous acid, generated by the almost instantaneous oxidation of Br- by Selectfluor in an aqueous milieu.
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Affiliation(s)
- Harshit Joshi
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66047, United States
| | - Debobrata Paul
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66047, United States
| | - Shyam Sathyamoorthi
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66047, United States
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14
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Wang JY, Zhang S, Yuan Q, Li G, Yan S. Catalytic Radical-Triggered Annulation/Iododifluoromethylation of Enynones for the Stereospecific Synthesis of 1-Indenones. J Org Chem 2023. [PMID: 37220028 DOI: 10.1021/acs.joc.3c00471] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A new Pd(II)-catalyzed annulation/iododifluoromethylation of enynones has been developed for the synthesis of versatile 1-indanones with moderate to good yields (26 examples). The present strategy enabled the concomitant incorporation of two important difluoroalkyl and iodo functionalities into 1-indenone skeletons with (E)-stereoselectivity. The mechanistic pathway was proposed, consisting of the difluoroalkyl radical-triggered α,β-conjugated addition/5-exo-dig cyclization/metal radical cross-coupling/reductive elimination cascade.
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Affiliation(s)
- Jia-Yin Wang
- School of Pharmacy, Continuous Flow Engineering Laboratory of National Petroleum and Chemical Industry, Changzhou University, Changzhou, Jiangsu 213164, China
| | - Sai Zhang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Qingkai Yuan
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Guigen Li
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Shenghu Yan
- School of Pharmacy, Continuous Flow Engineering Laboratory of National Petroleum and Chemical Industry, Changzhou University, Changzhou, Jiangsu 213164, China
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15
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Soro DM, Roque JB, Rackl JW, Park B, Payer S, Shi Y, Ruble JC, Kaledin AL, Baik MH, Musaev DG, Sarpong R. Photo- and Metal-Mediated Deconstructive Approaches to Cyclic Aliphatic Amine Diversification. J Am Chem Soc 2023; 145:11245-11257. [PMID: 37171220 DOI: 10.1021/jacs.3c01318] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Described herein are studies toward the core modification of cyclic aliphatic amines using either a riboflavin/photo-irradiation approach or Cu(I) and Ag(I) to mediate the process. Structural remodeling of cyclic amines is explored through oxidative C-N and C-C bond cleavage using peroxydisulfate (persulfate) as an oxidant. Ring-opening reactions to access linear aldehydes or carboxylic acids with flavin-derived photocatalysis or Cu salts, respectively, are demonstrated. A complementary ring-opening process mediated by Ag(I) facilitates decarboxylative Csp3-Csp2 coupling in Minisci-type reactions through a key alkyl radical intermediate. Heterocycle interconversion is demonstrated through the transformation of N-acyl cyclic amines to oxazines using Cu(II) oxidation of the alkyl radical. These transformations are investigated by computation to inform the proposed mechanistic pathways. Computational studies indicate that persulfate mediates oxidation of cyclic amines with concomitant reduction of riboflavin. Persulfate is subsequently reduced by formal hydride transfer from the reduced riboflavin catalyst. Oxidation of the cyclic aliphatic amines with a Cu(I) salt is proposed to be initiated by homolysis of the peroxy bond of persulfate followed by α-HAT from the cyclic amine and radical recombination to form an α-sulfate adduct, which is hydrolyzed to the hemiaminal. Investigation of the pathway to form oxazines indicates a kinetic preference for cyclization over more typical elimination pathways to form olefins through Cu(II) oxidation of alkyl radicals.
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Affiliation(s)
- David M Soro
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jose B Roque
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jonas W Rackl
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Bohyun Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Stefan Payer
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Yuan Shi
- Discovery Chemistry Research and Technologies, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - J Craig Ruble
- Discovery Chemistry Research and Technologies, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Alexey L Kaledin
- Cherry L. Emerson Center for Scientific Computation, and Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Mu-Hyun Baik
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Djamaladdin G Musaev
- Cherry L. Emerson Center for Scientific Computation, and Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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16
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Cao H, Histand G, Lin D. Selectfluor-Induced Oxidative Amination of N-Heteroaromatics with Purine. J Org Chem 2023; 88:5687-5695. [PMID: 37120834 DOI: 10.1021/acs.joc.3c00149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
An oxidative coupling reaction between purines and aromatic N-heterocycles was developed to synthesize a series of N-heteroaryl purine derivatives using Selectfluor as an oxidant at room temperature. This process uses a commercial oxidant, uses no base, metal, or other additives, is simple to carry out, and has a broad range of substrates.
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Affiliation(s)
- Haiyan Cao
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong 510641, China
| | - Gary Histand
- The International School of Advanced Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510640, China
| | - Dongen Lin
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong 510641, China
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17
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Holt E, Wang M, Harry SA, He C, Wang Y, Henriquez N, Xiang MR, Zhu A, Ghorbani F, Lectka T. An Electrochemical Approach to Directed Fluorination. J Org Chem 2023; 88:2557-2560. [PMID: 36702475 DOI: 10.1021/acs.joc.2c01886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Electrosynthesis has made a revival in the field of organic chemistry and, in particular, radical-mediated reactions. Herein, we report a simple directed, electrochemical C-H fluorination method. Employing a dabconium mediator, commercially available Selectfluor, and RVC electrodes, we provide a range of steroid-based substrates with competent regioselective directing groups, including enones, ketones, and hydroxy groups, as well as never reported before lactams, imides, lactones, and esters.
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Affiliation(s)
- Eric Holt
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Muyuan Wang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Stefan Andrew Harry
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Chengkun He
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Yuang Wang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Nicolas Henriquez
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Michael Richard Xiang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Andrea Zhu
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Fereshte Ghorbani
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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18
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Dai L, Zhang Z, Zhu G, Liu Y, Liu X, Zhang J, Rong L. Fluorohydroxylation and Hydration Reactions of para-Quinone Methides Promoted by Selectfluor. J Org Chem 2023; 88:1352-1363. [PMID: 36695008 DOI: 10.1021/acs.joc.2c02069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Selectfluor-promoted vicinal fluorohydroxylation and hydration reaction of para-quinone methides (p-QMs) were described, affording vicinal fluorohydrins and ketone/ether products in high yields. The hydration products were highly controlled by the electronic properties of substituents in the aromatic ring, and simultaneously, the amount of Selectfluor was completely different during the synthesis of ketone/ether products. This reaction also represents the first fluorohydroxylation of p-QMs, and the wide range of p-QMs makes the vicinal fluorohydroxylation of great significance.
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Affiliation(s)
- Lei Dai
- Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Zhou Zhang
- Department of Chemical Engineering &Technology, China University of Mining and Technology, Xuzhou, Jiangsu 221116, P. R. China
| | - Guangzhou Zhu
- Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Yun Liu
- Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Xiaoqin Liu
- Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Jinpeng Zhang
- Key Lab of Environment and Health, School of Public Health, Xuzhou Medical University, Xuzhou, Jiangsu 221004, P. R. China
| | - Liangce Rong
- Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
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19
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Hintz H, Bower J, Tang J, LaLama M, Sevov C, Zhang S. Copper-Catalyzed Electrochemical C-H Fluorination. CHEM CATALYSIS 2023; 3:100491. [PMID: 36743279 PMCID: PMC9894310 DOI: 10.1016/j.checat.2022.100491] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We report the systematic development of an electrooxidative methodology that translates stoichiometric C-H fluorination reactivity of an isolable CuIII fluoride complex into a catalytic process. The critical challenges of electrocatalysis with a highly reactive CuIII species were addressed by the judicious selection of electrolyte, F- source, and sacrificial electron acceptor. Catalyst-controlled C-H fluorination occurs with a preference for hydridic C-H bonds with high bond dissociation energies over weaker but less hydridic C-H bonds. The selectivity is driven by an oxidative asynchronous proton-coupled elelctron transfer (PCET) at an electrophilic CuIII-F complex. We further demonstrate that the asynchronicity factor of hydrogen atom transfer η can be used as a guideline to rationalize the selectivity of C-H fluorination.
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Affiliation(s)
- Heather Hintz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Jamey Bower
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Jinghua Tang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Matthew LaLama
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Christo Sevov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Shiyu Zhang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
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20
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Stangier M, Scheremetjew A, Ackermann L. Chemo- and Site-Selective Electro-Oxidative Alkane Fluorination by C(sp 3 )-H Cleavage. Chemistry 2022; 28:e202201654. [PMID: 35844078 PMCID: PMC9804291 DOI: 10.1002/chem.202201654] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Indexed: 01/05/2023]
Abstract
Electrochemical fluorinations of C(sp3 )-H bonds with a nucleophilic fluoride source have been accomplished in a chemo- and site-selective fashion, avoiding the use of electrophilic F+ sources and stoichiometric oxidants. The introduced metal-free strategy exhibits high functional group tolerance, setting the stage for late-stage fluorinations of biorelevant motifs. The synthetic utility of the C(sp3 )-H fluorination was reflected by subsequent one-pot arylation of the generated benzylic fluorides.
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Affiliation(s)
- Maximilian Stangier
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Alexej Scheremetjew
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Lutz Ackermann
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
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21
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Golden DL, Suh SE, Stahl SS. Radical C(sp3)-H functionalization and cross-coupling reactions. Nat Rev Chem 2022; 6:405-427. [PMID: 35965690 PMCID: PMC9364982 DOI: 10.1038/s41570-022-00388-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2022] [Indexed: 11/09/2022]
Abstract
C─H functionalization reactions are playing an increasing role in the preparation and modification of complex organic molecules, including pharmaceuticals, agrochemicals, and polymer precursors. Radical C─H functionalization reactions, initiated by hydrogen-atom transfer (HAT) and proceeding via open-shell radical intermediates, have been expanding rapidly in recent years. These methods introduce strategic opportunities to functionalize C(sp3)─H bonds. Examples include synthetically useful advances in radical-chain reactivity and biomimetic radical-rebound reactions. A growing number of reactions, however, proceed via "radical relay" whereby HAT generates a diffusible radical that is functionalized by a separate reagent or catalyst. The latter methods provide the basis for versatile C─H cross-coupling methods with diverse partners. In the present review, highlights of recent radical-chain and radical-rebound methods provide context for a survey of emerging radical-relay methods, which greatly expand the scope and utility of intermolecular C(sp3)─H functionalization and cross coupling.
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Affiliation(s)
- Dung L. Golden
- Department of Chemistry, University of Wisconsin–Madison, WI, USA
- These authors contributed equally: Dung L. Golden, Sung-Eun Suh
| | - Sung-Eun Suh
- Department of Chemistry, University of Wisconsin–Madison, WI, USA
- These authors contributed equally: Dung L. Golden, Sung-Eun Suh
- Department of Chemistry, Ajou University, Suwon, Republic of Korea
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin–Madison, WI, USA
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22
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Wu FW, Mao YJ, Pu J, Li HL, Ye P, Xu ZY, Lou SJ, Xu DQ. Ni-catalysed deamidative fluorination of amides with electrophilic fluorinating reagents. Org Biomol Chem 2022; 20:4091-4095. [PMID: 35522070 DOI: 10.1039/d2ob00519k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We describe here a Ni-catalysed deamidative fluorination of diverse amides with electrophilic fluorinating reagents. Different types of amides including aromatic amides and olefinic amides were well compatible, affording the corresponding acyl fluorides in good to excellent yields.
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Affiliation(s)
- Feng-Wei Wu
- Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Yang-Jie Mao
- Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Jun Pu
- Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Huan-Le Li
- Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Peng Ye
- Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Zhen-Yuan Xu
- Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Shao-Jie Lou
- Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Dan-Qian Xu
- Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
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23
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Galeotti M, Vicens L, Salamone M, Costas M, Bietti M. Resolving Oxygenation Pathways in Manganese-Catalyzed C(sp 3)-H Functionalization via Radical and Cationic Intermediates. J Am Chem Soc 2022; 144:7391-7401. [PMID: 35417154 PMCID: PMC9052745 DOI: 10.1021/jacs.2c01466] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
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The C(sp3)–H bond oxygenation of the cyclopropane-containing
mechanistic probes 6-tert-butylspiro[2.5]octane and
spiro[2.5]octane with hydrogen peroxide catalyzed by manganese complexes
bearing aminopyridine tetradentate ligands has been studied. Mixtures
of unrearranged and rearranged oxygenation products (alcohols, ketones,
and esters) are obtained, suggesting the involvement of cationic intermediates
and the contribution of different pathways following the initial hydrogen
atom transfer-based C–H bond cleavage step. Despite such a
complex mechanistic scenario, a judicious choice of the catalyst structure
and reaction conditions (solvent, temperature, and carboxylic acid)
could be employed to resolve these oxygenation pathways, leading,
with the former substrate, to conditions where a single unrearranged
or rearranged product is obtained in good isolated yield. Taken together,
the work demonstrates an unprecedented ability to precisely direct
the chemoselectivity of the C–H oxidation reaction, discriminating
among multiple pathways. In addition, these results conclusively demonstrate
that stereospecific C(sp3)–H oxidation can take
place via a cationic intermediate and that this path can become exclusive
in governing product formation, expanding the available toolbox of
aliphatic C–H bond oxygenations. The implications of these
findings are discussed in the framework of the development of synthetically
useful C–H functionalization procedures and the associated
mechanistic features.
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Affiliation(s)
- Marco Galeotti
- Dipartimento di Scienze e Tecnologie Chimiche, Università"Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Laia Vicens
- QBIS Research Group, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università"Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Miquel Costas
- QBIS Research Group, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università"Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
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24
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Visible-light induced transition-metal and photosensitizer-free conversion of aldehydes to acyl fluorides under mild conditions. GREEN SYNTHESIS AND CATALYSIS 2022. [DOI: 10.1016/j.gresc.2022.04.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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25
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Paik A, Paul S, Bhowmik S, Das R, Naveen T, Rana S. Recent Advances in First Row Transition Metal Mediated C‐H Halogenation of (Hetero)arenes and Alkanes. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202200060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Aniruddha Paik
- University of North Bengal Department of Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India - 734013 734013 Siliguri INDIA
| | - Sabarni Paul
- University of North Bengal Department of Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India - 734013 734013 Siliguri INDIA
| | - Sabyasachi Bhowmik
- University of North Bengal Department of Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India - 734013 734013 Siliguri INDIA
| | - Rahul Das
- University of North Bengal Department of Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India - 734013 734013 Siliguri INDIA
| | - Togati Naveen
- Sardar Vallabhbhai National Institute of Technology Department of Chemistry 395007 Surat INDIA
| | - Sujoy Rana
- University of North Bengal Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India, 734013 734013 Siliguri INDIA
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26
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Fazekas TJ, Alty JW, Neidhart EK, Miller AS, Leibfarth FA, Alexanian EJ. Diversification of aliphatic C-H bonds in small molecules and polyolefins through radical chain transfer. Science 2022; 375:545-550. [PMID: 35113718 PMCID: PMC8889563 DOI: 10.1126/science.abh4308] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The ability to selectively introduce diverse functionality onto hydrocarbons is of substantial value in the synthesis of both small molecules and polymers. Herein, we report an approach to aliphatic carbon-hydrogen bond diversification using radical chain transfer featuring an easily prepared O-alkenylhydroxamate reagent, which upon mild heating facilitates a range of challenging or previously undeveloped aliphatic carbon-hydrogen bond functionalizations of small molecules and polyolefins. This broad reaction platform enabled the functionalization of postconsumer polyolefins in infrastructure used to process plastic waste. Furthermore, the chemoselective placement of ionic functionality onto a branched polyolefin using carbon-hydrogen bond functionalization upcycled the material from a thermoplastic into a tough elastomer with the tensile properties of high-value polyolefin ionomers.
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Affiliation(s)
- Timothy J Fazekas
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jill W Alty
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Eliza K Neidhart
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Austin S Miller
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Frank A Leibfarth
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Erik J Alexanian
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
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27
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Computational Study of Key Mechanistic Details for a Proposed Copper (I)-Mediated Deconstructive Fluorination of N-Protected Cyclic Amines. Top Catal 2022; 65:418-432. [PMID: 35197715 DOI: 10.1007/s11244-021-01443-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Using calculations, we show that a proposed Cu(I)-mediated deconstructive fluorination of N-benzoylated cyclic amines with Selectfluor® is feasible and may proceed through: (a) substrate coordination to a Cu(I) salt, (b) iminium ion formation followed by conversion to a hemiaminal, and (c) fluorination involving C-C cleavage of the hemiaminal. The iminium ion formation is calculated to proceed via a F-atom coupled electron transfer (FCET) mechanism to form, formally, a product arising from oxidative addition coupled with electron transfer (OA + ET). The subsequent β-C-C cleavage/fluorination of the hemiaminal intermediate may proceed via either ring-opening or deformylative fluorination pathways. The latter pathway is initiated by opening of the hemiaminal to give an aldehyde, followed by formyl H-atom abstraction by a TEDA2+ radical dication, decarbonylation, and fluorination of the C3-radical center by another equivalent of Selectfluor®. In general, the mechanism for the proposed Cu(I)- mediated deconstructive C-H fluorination of N-benzoylated cyclic amines (LH) by Selectfluor® was calculated to proceed analogously to our previously reported Ag(I)-mediated reaction. In comparison to the Ag(I)-mediated process, in the Cu(I)-mediated reaction the iminium ion formation and hemiaminal fluorination have lower associated energy barriers, whereas the product release and catalyst re-generation steps have higher barriers.
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28
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Kaur N, Ziegelmeyer EC, Farinde ON, Truong JT, Huynh MM, Li W. Visible light bromide catalysis for oxazoline, pyrrolidine, and dihydrooxazine syntheses via C sp3-H functionalizations. Chem Commun (Camb) 2021; 57:10387-10390. [PMID: 34542120 DOI: 10.1039/d1cc04588a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A catalytic benzylic Csp3-H functionalization protocol is described here. This visible light-mediated process is centered on the utilization of a bromide catalyst and oxidant to generate a nitrogen (N)-centered radical for a site-selective hydrogen atom transfer (HAT) process. This strategy enabled the unconventional syntheses of a number of N-heterocycles dependent on the amide identity. We also discovered a nucleophilicity-dependent kinetic resolution for stereochemical differentiation of Csp3-H bonds that enabled the stereoselective synthesis of cis- and trans-oxazolines.
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Affiliation(s)
- Navdeep Kaur
- Department of Chemistry and Biochemistry and School of Green Chemistry and Engineering, The University of Toledo, Toledo, Ohio 43606, USA.
| | - Elizabeth C Ziegelmeyer
- Department of Chemistry and Biochemistry and School of Green Chemistry and Engineering, The University of Toledo, Toledo, Ohio 43606, USA.
| | - Olutayo N Farinde
- Department of Chemistry and Biochemistry and School of Green Chemistry and Engineering, The University of Toledo, Toledo, Ohio 43606, USA.
| | - Jonathon T Truong
- Department of Chemistry and Biochemistry and School of Green Chemistry and Engineering, The University of Toledo, Toledo, Ohio 43606, USA.
| | - Michelle M Huynh
- Department of Chemistry and Biochemistry and School of Green Chemistry and Engineering, The University of Toledo, Toledo, Ohio 43606, USA.
| | - Wei Li
- Department of Chemistry and Biochemistry and School of Green Chemistry and Engineering, The University of Toledo, Toledo, Ohio 43606, USA.
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29
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30
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Chang Z, Huang J, Wang S, Chen G, Zhao H, Wang R, Zhao D. Copper catalyzed late-stage C(sp 3)-H functionalization of nitrogen heterocycles. Nat Commun 2021; 12:4342. [PMID: 34267229 PMCID: PMC8282657 DOI: 10.1038/s41467-021-24671-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 06/21/2021] [Indexed: 11/15/2022] Open
Abstract
Nitrogen heterocycle represents a ubiquitous skeleton in natural products and drugs. Late-stage C(sp3)-H bond functionalization of N-heterocycles with broad substrate scope remains a challenge and of particular significance to modern chemical synthesis and pharmaceutical chemistry. Here, we demonstrate copper-catalysed late-stage C(sp3)-H functionalizaion of N-heterocycles using commercially available catalysts under mild reaction conditions. We have investigated 8 types of N-heterocycles which are usually found as medicinally important skeletons. The scope and utility of this approach are demonstrated by late-stage C(sp3)-H modification of these heterocycles including a number of pharmaceuticals with a broad range of nucleophiles, e.g. methylation, arylation, azidination, mono-deuteration and glycoconjugation etc. Preliminary mechanistic studies reveal that the reaction undergoes a C-H fluorination process which is followed by a nucleophilic substitution.
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Affiliation(s)
- Zhe Chang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Jialin Huang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Si Wang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Geshuyi Chen
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Heng Zhao
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Rui Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
| | - Depeng Zhao
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China.
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31
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Donzel M, Karabiyikli D, Cotos L, Elhabiri M, Davioud‐Charvet E. Direct C−H Radical Alkylation of 1,4‐Quinones. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100452] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Maxime Donzel
- UMR7042 Université de Strasbourg-CNRS-UHA Laboratoire d'Innovation Moléculaire et Applications (LIMA) Team Bio (IN) organic and Medicinal Chemistry European School of Chemistry, Polymers and Materials (ECPM) 25 Rue Becquerel Strasbourg 67087 France
| | - Deniz Karabiyikli
- UMR7042 Université de Strasbourg-CNRS-UHA Laboratoire d'Innovation Moléculaire et Applications (LIMA) Team Bio (IN) organic and Medicinal Chemistry European School of Chemistry, Polymers and Materials (ECPM) 25 Rue Becquerel Strasbourg 67087 France
| | - Leandro Cotos
- UMR7042 Université de Strasbourg-CNRS-UHA Laboratoire d'Innovation Moléculaire et Applications (LIMA) Team Bio (IN) organic and Medicinal Chemistry European School of Chemistry, Polymers and Materials (ECPM) 25 Rue Becquerel Strasbourg 67087 France
| | - Mourad Elhabiri
- UMR7042 Université de Strasbourg-CNRS-UHA Laboratoire d'Innovation Moléculaire et Applications (LIMA) Team Bio (IN) organic and Medicinal Chemistry European School of Chemistry, Polymers and Materials (ECPM) 25 Rue Becquerel Strasbourg 67087 France
| | - Elisabeth Davioud‐Charvet
- UMR7042 Université de Strasbourg-CNRS-UHA Laboratoire d'Innovation Moléculaire et Applications (LIMA) Team Bio (IN) organic and Medicinal Chemistry European School of Chemistry, Polymers and Materials (ECPM) 25 Rue Becquerel Strasbourg 67087 France
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32
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Suh SE, Nkulu LE, Lin S, Krska SW, Stahl SS. Benzylic C-H isocyanation/amine coupling sequence enabling high-throughput synthesis of pharmaceutically relevant ureas. Chem Sci 2021; 12:10380-10387. [PMID: 34377424 PMCID: PMC8336431 DOI: 10.1039/d1sc02049h] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/28/2021] [Indexed: 12/29/2022] Open
Abstract
C(sp3)–H functionalization methods provide an ideal synthetic platform for medicinal chemistry; however, such methods are often constrained by practical limitations. The present study outlines a C(sp3)–H isocyanation protocol that enables the synthesis of diverse, pharmaceutically relevant benzylic ureas in high-throughput format. The operationally simple C–H isocyanation method shows high site selectivity and good functional group tolerance, and uses commercially available catalyst components and reagents [CuOAc, 2,2′-bis(oxazoline) ligand, (trimethylsilyl)isocyanate, and N-fluorobenzenesulfonimide]. The isocyanate products may be used without isolation or purification in a subsequent coupling step with primary and secondary amines to afford hundreds of diverse ureas. These results provide a template for implementation of C–H functionalization/cross-coupling in drug discovery. A copper-based catalyst system composed of commercially available reagents enables C–H isocyanation with exquisite (hetero)benzylic site selectivity, enabling high-throughput access to pharmaceutically relevant ureas via coupling with amines.![]()
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Affiliation(s)
- Sung-Eun Suh
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison Wisconsin 53706 USA
| | - Leah E Nkulu
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison Wisconsin 53706 USA
| | - Shishi Lin
- Chemistry Capabilities for Accelerating Therapeutics, Merck & Co., Inc. 2000 Galloping Hill Road Kenilworth New Jersey 07033 USA
| | - Shane W Krska
- Chemistry Capabilities for Accelerating Therapeutics, Merck & Co., Inc. 2000 Galloping Hill Road Kenilworth New Jersey 07033 USA
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison Wisconsin 53706 USA
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33
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34
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Capilato JN, Lectka T. Arene Amination Instead of Fluorination: Substitution Pattern Governs the Reactivity of Dialkoxybenzenes with Selectfluor. J Org Chem 2021; 86:5771-5777. [PMID: 33787260 DOI: 10.1021/acs.joc.1c00231] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Arene substitution patterns are well-known to affect the regioselectivity of a given transformation but not necessarily the type of reactivity. Herein, we report that the substitution pattern of alkoxyarenes dictates whether a putative one-electron or two-electron reaction predominates in reactions with Selectfluor. A series of amination products is presented, resulting from the single-electron oxidation of electron-rich arenes followed by direct C-H to C-N bond formation. We demonstrate the ability of this transformation to synthesize medicinally and biologically relevant nitrogen heterocycles. Lastly, this unusual "mechanistic switch" is probed with computational chemistry and competition experiments.
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Affiliation(s)
- Joseph N Capilato
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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35
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Liu Z, Wang Y, Huo J, Li XJ, Li S, Song X. Selectfluor-Promoted Intramolecular N-S Bond Formation of α-Carbamoyl Ketene Dithioacetals in the Presence of Water: Synthesis of Multifunctionalized Isothiazolones. J Org Chem 2021; 86:5506-5517. [PMID: 33797258 DOI: 10.1021/acs.joc.0c03036] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A practical and efficient protocol toward fully substituted isothiazolones through Selectfluor-mediated intramolecular oxidative annulation of α-carbamoyl ketene dithioacetals has been developed in the presence of H2O and metal-free conditions. Notably, the experimental results reveal that H2O was crucial to the formation of new N-S bonds and the elimination of alkyl group from the sulfur atom. This protocol provides readily prepared substrates and possesses good functional group tolerance, mild reaction conditions, and operational simplicity, which provides potential access to applications in the pharmaceutical chemistry.
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Affiliation(s)
- Zheng Liu
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, P. R. China
| | - Youkun Wang
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, P. R. China
| | - Jianfeng Huo
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, P. R. China
| | - Xiao-Jun Li
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, P. R. China
| | - Shengnan Li
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, P. R. China
| | - Xiaoning Song
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, P. R. China
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36
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Matsumoto A, Wang Z, Maruoka K. Radical-Mediated Activation of Esters with a Copper/Selectfluor System: Synthesis of Bulky Amides and Peptides. J Org Chem 2021; 86:5401-5411. [PMID: 33720721 DOI: 10.1021/acs.joc.1c00188] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we describe a new approach for the activation of esters via a radical-mediated process enabled by a copper/Selectfluor system. A variety of para-methoxybenzyl esters derived from bulky carboxylic acids and amino acids can be easily converted into the corresponding acyl fluorides, directly used in the one-pot synthesis of amides and peptides. As a proof of concept, this method was applied to the iterative formation of sterically hindered amide bonds.
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Affiliation(s)
- Akira Matsumoto
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Zhe Wang
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Keiji Maruoka
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.,School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China
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37
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Roque JB, Sarpong R, Musaev DG. Key Mechanistic Features of the Silver(I)-Mediated Deconstructive Fluorination of Cyclic Amines: Multistate Reactivity versus Single-Electron Transfer. J Am Chem Soc 2021; 143:3889-3900. [DOI: 10.1021/jacs.0c13061] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Jose B. Roque
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Djamaladdin G. Musaev
- Cherry L. Emerson Center for Scientific Computation, and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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38
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Rozatian N, Hodgson DRW. Reactivities of electrophilic N-F fluorinating reagents. Chem Commun (Camb) 2021; 57:683-712. [PMID: 33367354 DOI: 10.1039/d0cc06339h] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Electrophilic fluorination represents one of the most direct and useful methods available for the selective introduction of fluorine into organic compounds. Electrophilic fluorinating reagents of the N-F class have revolutionised the incorporation of fluorine atoms into both pharmaceutically- and agrochemically-important substrates. Since the earliest N-F reagents were commercialised in the 1990s, their reactivities have been investigated using qualitative and, more recently, quantitative methods. This review discusses the different experimental approaches employed to determine reactivities of N-F reagents, focussing on the kinetics studies reported in recent years. We make critical evaluations of the experimental approaches against each other, theoretical approaches, and their applicability towards practical problems. The opportunities for achieving more efficient synthetic electrophilic fluorination processes through kinetic understanding are highlighted.
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Affiliation(s)
- Neshat Rozatian
- Chemistry Department, Durham University, South Road, Durham, UKDH1 3LE.
| | - David R W Hodgson
- Chemistry Department, Durham University, South Road, Durham, UKDH1 3LE.
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39
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Muñoz-Molina JM, Belderrain TR, Pérez PJ. Recent Advances in Copper-Catalyzed Radical C–H Bond Activation Using N–F Reagents. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/s-0040-1707234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This Short Review is aimed at giving an update in the area of copper-catalyzed C–H functionalization involving nitrogen-centered radicals generated from substrates containing N–F bonds. These processes include intermolecular Csp3–H bond functionalization, remote Csp3–H bond functionalization via intramolecular hydrogen atom transfer (HAT), and Csp2–H bond functionalization, which might be of potential use in industrial applications in the future.1 Introduction2 Intermolecular Csp3–H Functionalization3 Remote Csp3–H Functionalization4 Csp2–H Functionalization5 Conclusion
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Affiliation(s)
| | | | - Pedro J. Pérez
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva
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40
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Zhu S, Yang H, Jiang A, Zhou B, Han Y, Yan C, Shi Y, Hou H. Copper-Catalyzed Bromodifluoroacetylative Cyclization of Enynes. J Org Chem 2020; 85:15667-15675. [PMID: 33176101 DOI: 10.1021/acs.joc.0c02114] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A copper-catalyzed bromodifluoroacetylative cyclization reaction is described. The treatment of bromodifluoroacete derivatives by CuI and B2Pin2 enables difluoroalkyl radical generation and triggers the radical addition/cyclization/bromination sequences. Bromodifluoroacetyl-derived ester, amide, and ketone were compatible and gave various vinyl C-Br bonds containing functionalized heterocycles in good yields.
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Affiliation(s)
- Shaoqun Zhu
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China
| | - Haibo Yang
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China
| | - Along Jiang
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China
| | - Bing Zhou
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China
| | - Ying Han
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China
| | - Chaoguo Yan
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China
| | - Yaocheng Shi
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China
| | - Hong Hou
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China
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41
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Kong Y, Xu W, Liu X, Weng J. Visible light-induced hydroxyalkylation of 2H-benzothiazoles with alcohols via selectfluor oxidation. CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2020.05.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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42
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Yakubov S, Barham JP. Photosensitized direct C-H fluorination and trifluoromethylation in organic synthesis. Beilstein J Org Chem 2020; 16:2151-2192. [PMID: 32952732 PMCID: PMC7476599 DOI: 10.3762/bjoc.16.183] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/17/2020] [Indexed: 12/11/2022] Open
Abstract
The importance of fluorinated products in pharmaceutical and medicinal chemistry has necessitated the development of synthetic fluorination methods, of which direct C-H fluorination is among the most powerful. Despite the challenges and limitations associated with the direct fluorination of unactivated C-H bonds, appreciable advancements in manipulating the selectivity and reactivity have been made, especially via transition metal catalysis and photochemistry. Where transition metal catalysis provides one strategy for C-H bond activation, transition-metal-free photochemical C-H fluorination can provide a complementary selectivity via a radical mechanism that proceeds under milder conditions than thermal radical activation methods. One exciting development in C-F bond formation is the use of small-molecule photosensitizers, allowing the reactions i) to proceed under mild conditions, ii) to be user-friendly, iii) to be cost-effective and iv) to be more amenable to scalability than typical photoredox-catalyzed methods. In this review, we highlight photosensitized C-H fluorination as a recent strategy for the direct and remote activation of C-H (especially C(sp3)-H) bonds. To guide the readers, we present the developing mechanistic understandings of these reactions and exemplify concepts to assist the future planning of reactions.
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Affiliation(s)
- Shahboz Yakubov
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
| | - Joshua P Barham
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
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Ghorbani F, Harry SA, Capilato JN, Pitts CR, Joram J, Peters GN, Tovar JD, Smajlagic I, Siegler MA, Dudding T, Lectka T. Carbonyl-Directed Aliphatic Fluorination: A Special Type of Hydrogen Atom Transfer Beats Out Norrish II. J Am Chem Soc 2020; 142:14710-14724. [PMID: 32786786 DOI: 10.1021/jacs.0c07004] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recently, our group reported that enone and ketone functional groups, upon photoexcitation, can direct site-selective sp3 C-H fluorination in terpenoid derivatives. How this transformation actually occurred remained mysterious, as a significant number of mechanistic possibilities came to mind. Herein, we report a comprehensive study describing the reaction mechanism through kinetic studies, isotope-labeling experiments, 19F NMR, electrochemical studies, synthetic probes, and computational experiments. To our surprise, the mechanism suggests intermolecular hydrogen atom transfer (HAT) chemistry is at play, rather than classical Norrish hydrogen atom abstraction as initially conceived. What is more, we discovered a unique role for photopromoters such as benzil and related compounds that necessitates their chemical transformation through fluorination in order to be effective. Our findings provide documentation of an unusual form of directed HAT and are of crucial importance for defining the necessary parameters for the development of future methods.
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Affiliation(s)
- Fereshte Ghorbani
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Stefan Andrew Harry
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Joseph N Capilato
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Cody Ross Pitts
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Jacob Joram
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Garvin N Peters
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - John D Tovar
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Ivor Smajlagic
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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44
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Bafaluy D, Georgieva Z, Muñiz K. Iodine Catalysis for C(sp 3 )-H Fluorination with a Nucleophilic Fluorine Source. Angew Chem Int Ed Engl 2020; 59:14241-14245. [PMID: 32421217 DOI: 10.1002/anie.202004902] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Indexed: 01/13/2023]
Abstract
Iodine catalysis was developed for aliphatic fluorination through light-promoted homolytic C-H bond cleavage. The intermediary formation of amidyl radicals enables selective C-H functionalization via carbon-centered radicals. For the subsequent C-F bond formation, previous methods have typically been limited by a requirement for electrophilic fluorine reagents. We here demonstrate that the intermediary instalment of a carbon-iodine bond sets the stage for an umpolung, thereby establishing an unprecedented nucleophilic fluorination pathway.
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Affiliation(s)
- Daniel Bafaluy
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain
| | - Zoritsa Georgieva
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain
| | - Kilian Muñiz
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain
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45
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Buss JA, Vasilopoulos A, Golden DL, Stahl SS. Copper-Catalyzed Functionalization of Benzylic C-H Bonds with N-Fluorobenzenesulfonimide: Switch from C-N to C-F Bond Formation Promoted by a Redox Buffer and Brønsted Base. Org Lett 2020; 22:5749-5752. [PMID: 32790419 PMCID: PMC7446155 DOI: 10.1021/acs.orglett.0c02239] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A copper catalyst in combination with N-fluorobenzenesulfonimide (NFSI) has been reported to functionalize benzylic C-H bonds to the corresponding benzylic sulfonimides via C-N coupling. Here, we reported a closely related Cu-catalyzed method with NFSI that instead leads to C-F coupling. This switch in selectivity arises from changes to the reaction conditions (Cu/ligand ratio, temperature, addition of base) and further benefits from inclusion of MeB(OH)2 in the reaction. MeB(OH)2 is shown to serve as a "redox buffer" in the reaction, responsible for rescuing inactive Cu(II) for continued promotion of fluorination reactivity.
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Affiliation(s)
- Joshua A. Buss
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Aristidis Vasilopoulos
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Dung L. Golden
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
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46
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Bafaluy D, Georgieva Z, Muñiz K. Iodine Catalysis for C(sp
3
)–H Fluorination with a Nucleophilic Fluorine Source. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004902] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Daniel Bafaluy
- Institute of Chemical Research of Catalonia, ICIQ The Barcelona Institute of Science and Technology Av. Països Catalans, 16 43007 Tarragona Spain
| | - Zoritsa Georgieva
- Institute of Chemical Research of Catalonia, ICIQ The Barcelona Institute of Science and Technology Av. Països Catalans, 16 43007 Tarragona Spain
| | - Kilian Muñiz
- Institute of Chemical Research of Catalonia, ICIQ The Barcelona Institute of Science and Technology Av. Països Catalans, 16 43007 Tarragona Spain
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47
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Artault M, Mokhtari N, Cantin T, Martin-Mingot A, Thibaudeau S. Superelectrophilic Csp 3-H bond fluorination of aliphatic amines in superacid: the striking role of ammonium-carbenium dications. Chem Commun (Camb) 2020; 56:5905-5908. [PMID: 32342071 DOI: 10.1039/d0cc02081h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The superacid-promoted electrophilic Csp3-H bond activation of aliphatic amines generates superelectrophilic species that can be subsequently fluorinated. Demonstrated by low-temperature in situ NMR experiments, the ammonium-carbenium dications, crucial for this reaction, can also react with C-H bonds opening future synthesis perspectives for this mode of activation.
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Affiliation(s)
- M Artault
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
| | - N Mokhtari
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
| | - T Cantin
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
| | - A Martin-Mingot
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
| | - S Thibaudeau
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
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48
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Aguilar Troyano FJ, Merkens K, Gómez‐Suárez A. Selectfluor® Radical Dication (TEDA
2+.
) – A Versatile Species in Modern Synthetic Organic Chemistry. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.202000196] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | - Kay Merkens
- Organic ChemistryBergische Universität Wuppertal Gaußstr. 20 42119 Wuppertal Germany
| | - Adrián Gómez‐Suárez
- Organic ChemistryBergische Universität Wuppertal Gaußstr. 20 42119 Wuppertal Germany
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49
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Selective C-H trifluoromethoxylation of (hetero)arenes as limiting reagent. Nat Commun 2020; 11:2569. [PMID: 32444828 PMCID: PMC7244481 DOI: 10.1038/s41467-020-16451-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 05/04/2020] [Indexed: 02/01/2023] Open
Abstract
Methods for direct C-H trifluoromethoxylation of arenes and heteroarenes are rare, despite the importance of trifluoromethoxylated compounds for pharmaceuticals, agrochemicals, and material sciences. Especially selective C-H trifluoromethoxylation of pyridines remains a formidable challenge. Here we show a general late-stage C-H trifluoromethoxylation of arenes and heteroarenes as limiting reagent with trifluoromethoxide anion. The reaction is mediated by silver salts under mild reaction conditions, exhibiting broad substrate scope and wide functional-group compatibility. In addition, ortho-position selective C-H trifluoromethoxylation of pyridines is observed. The method is not only applicable to the gram-scale synthesis of trifluoromethoxylated products but also allows efficient late-stage C-H trifluoromethoxylation of marketed small-molecule drugs, common pharmacophores and natural products. Selective C-H trifluoromethoxylation of pyridines remains a formidable synthetic challenge. Here, the authors report a silver-mediated late-stage C-H trifluoromethoxylation of arenes and heteroarenes as limiting reagents with trifluoromethoxide anion.
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50
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Yoshii T, Tsuzuki S, Sakurai S, Sakamoto R, Jiang J, Hatanaka M, Matsumoto A, Maruoka K. N-Hydroxybenzimidazole as a structurally modifiable platform for N-oxyl radicals for direct C-H functionalization reactions. Chem Sci 2020; 11:5772-5778. [PMID: 32832053 PMCID: PMC7416693 DOI: 10.1039/d0sc02134b] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/16/2020] [Indexed: 11/21/2022] Open
Abstract
A novel class of N-oxy radicals based on flexibly modifiable N-hydroxybenzimidazole skeleton was designed and applied to C–H functionalization reactions.
Methods for direct functionalization of C–H bonds mediated by N-oxyl radicals constitute a powerful tool in modern organic synthesis. While several N-oxyl radicals have been developed to date, the lack of structural diversity for these species has hampered further progress in this field. Here we designed a novel class of N-oxyl radicals based on N-hydroxybenzimidazole, and applied them to the direct C–H functionalization reactions. The flexibly modifiable features of these structures enabled facile tuning of their catalytic performance. Moreover, with these organoradicals, we have developed a metal-free approach for the synthesis of acyl fluorides via direct C–H fluorination of aldehydes under mild conditions.
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Affiliation(s)
- Tomomi Yoshii
- Department of Chemistry , Graduate School of Science , Kyoto University , Sakyo , Kyoto 606-8502 , Japan .
| | - Saori Tsuzuki
- Department of Chemistry , Graduate School of Science , Kyoto University , Sakyo , Kyoto 606-8502 , Japan .
| | - Shunya Sakurai
- Department of Chemistry , Graduate School of Science , Kyoto University , Sakyo , Kyoto 606-8502 , Japan .
| | - Ryu Sakamoto
- Department of Chemistry , Graduate School of Science , Kyoto University , Sakyo , Kyoto 606-8502 , Japan .
| | - Julong Jiang
- Institute for Research Initiatives , Division for Research Strategy , Graduate School of Materials Science , Data Science Center , Nara Institute of Science and Technology , Ikoma , Nara 630-0192 , Japan
| | - Miho Hatanaka
- Institute for Research Initiatives , Division for Research Strategy , Graduate School of Materials Science , Data Science Center , Nara Institute of Science and Technology , Ikoma , Nara 630-0192 , Japan.,PRESTO , Japan Science and Technology (JST) , 4-1-8 Honcho , Kawaguchi , Saitama 332-0012 , Japan
| | - Akira Matsumoto
- Graduate School of Pharmaceutical Sciences , Kyoto University , Sakyo , Kyoto 606-8501 , Japan
| | - Keiji Maruoka
- Department of Chemistry , Graduate School of Science , Kyoto University , Sakyo , Kyoto 606-8502 , Japan . .,Graduate School of Pharmaceutical Sciences , Kyoto University , Sakyo , Kyoto 606-8501 , Japan.,School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
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