1
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Hanania N, Eghbarieh N, Masarwa A. PolyBorylated Alkenes as Energy-Transfer Reactive Groups: Access to Multi-Borylated Cyclobutanes Combined with Hydrogen Atom Transfer Event. Angew Chem Int Ed Engl 2024; 63:e202405898. [PMID: 38603554 DOI: 10.1002/anie.202405898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/11/2024] [Accepted: 04/11/2024] [Indexed: 04/13/2024]
Abstract
While polyborylated alkenes are being recognized for their elevated status as highly valuable reagents in modern organic synthesis, allowing efficient access to a diverse array of transformations, including the formation of C-C and C-heteroatom bonds, their potential as energy-transfer reactive groups has remained unexplored. Yet, this potential holds the key to generating elusive polyborylated biradical species, which can be captured by olefins, thereby leading to the construction of new highly-borylated scaffolds. Herein, we report a designed energy-transfer strategy for photosensitized [2+2]-cycloadditions of poly-borylated alkenes with various olefins enabling the regioselective synthesis of diverse poly-borylated cyclobutane motifs, including the 1,1-di-, 1,1,2-tri-, and 1,1,2,2-tetra-borylated cyclobutanes. In fact, these compounds belong to a family that presently lacks efficient synthetic pathways. Interestingly, when α-methylstyrene was used, the reaction involves an interesting 1,5-hydrogen atom transfer (HAT). Mechanistic deuterium-labeling studies have provided insight into the outcome of 1,5-hydrogen atom transfer process. In addition, the polyborylated cyclobutanes are then demonstrated to be useful in selective oxidation processes resulting in the formation of cyclobutanones and γ-lactones.
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Affiliation(s)
- Nicole Hanania
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, and Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Nadim Eghbarieh
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, and Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Ahmad Masarwa
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, and Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
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2
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McGhie L, Marotta A, Loftus PO, Seeberger PH, Funes-Ardoiz I, Molloy JJ. Photogeneration of α-Bimetalloid Radicals via Selective Activation of Multifunctional C1 Units. J Am Chem Soc 2024; 146:15850-15859. [PMID: 38805091 PMCID: PMC11177267 DOI: 10.1021/jacs.4c02261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/12/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
Light-driven strategies that enable the chemoselective activation of a specific bond in multifunctional systems are comparatively underexplored in comparison to transition-metal-based technologies, yet desirable when considering the controlled exploration of chemical space. With the current drive to discover next-generation therapeutics, reaction design that enables the strategic incorporation of an sp3 carbon center, containing multiple synthetic handles for the subsequent exploration of chemical space would be highly enabling. Here, we describe the photoactivation of ambiphilic C1 units to generate α-bimetalloid radicals using only a Lewis base and light source to directly activate the C-I bond. Interception of these transient radicals with various SOMOphiles enables the rapid synthesis of organic scaffolds containing synthetic handles (B, Si, and Ge) for subsequent orthogonal activation. In-depth theoretical and mechanistic studies reveal the prominent role of 2,6-lutidine in forming a photoactive charge transfer complex and in stabilizing in situ generated iodine radicals, as well as the influential role of the boron p-orbital in the activation/weakening of the C-I bond. This simple and efficient methodology enabled expedient access to functionalized 3D frameworks that can be further derivatized using available technologies for C-B and C-Si bond activation.
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Affiliation(s)
- Lewis McGhie
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
- Department
of Chemistry and Biochemistry, Freie Universität
Berlin, Berlin 14195, Germany
| | - Alessandro Marotta
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
- Department
of Chemistry and Biochemistry, Freie Universität
Berlin, Berlin 14195, Germany
| | - Patrick O. Loftus
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
| | - Peter H. Seeberger
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
- Department
of Chemistry and Biochemistry, Freie Universität
Berlin, Berlin 14195, Germany
| | - Ignacio Funes-Ardoiz
- Department
of Chemistry, Instituto de Investigación Química de
la Universidad de La Rioja (IQUR), Universidad
de La Rioja Madre de Dios 53, Logroño 26004, Spain
| | - John J. Molloy
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
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3
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Kweon B, Blank L, Soika J, Messara A, Daniliuc CG, Gilmour R. Regio- and Stereo-Selective Isomerization of Borylated 1,3-Dienes Enabled by Selective Energy Transfer Catalysis. Angew Chem Int Ed Engl 2024; 63:e202404233. [PMID: 38545942 DOI: 10.1002/anie.202404233] [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: 03/01/2024] [Indexed: 04/23/2024]
Abstract
Configurationally-defined dienes are pervasive across the bioactive natural product spectrum, where they typically manifest themselves as sorbic acid-based fragments. These C5 motifs reflect the biosynthesis algorithms that facilitate their construction. To complement established biosynthetic paradigms, a chemical platform to facilitate the construction of stereochemically defined, functionalizable dienes by light-enabled isomerization has been devised. Enabled by selective energy transfer catalysis, a variety of substituted β-boryl sorbic acid derivatives can be isomerized in a regio- and stereo-selective manner (up to 97 : 3). Directionality is guided by a stabilizing nO→pB interaction in the product: this constitutes a formal anti-hydroboration of the starting alkyne. This operationally simple reaction employs low catalyst loadings (1 mol %) and is complete in 1 h. X-ray analysis supports the hypothesis that the nO→pB interaction leads to chromophore bifurcation: this provides a structural foundation for selective energy transfer.
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Affiliation(s)
- Byeongseok Kweon
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Lukas Blank
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Julia Soika
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Amélia Messara
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Constantin G Daniliuc
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Ryan Gilmour
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
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4
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Boudjelel M, Zhong J, Ballerini L, Vanswearingen I, Al-Dhufari R, Malapit CA. Electrochemical Generation of Aryl Radicals from Organoboron Reagents Enabled by Pulsed Electrosynthesis. Angew Chem Int Ed Engl 2024:e202406203. [PMID: 38753725 DOI: 10.1002/anie.202406203] [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: 04/01/2024] [Revised: 05/15/2024] [Accepted: 05/15/2024] [Indexed: 05/18/2024]
Abstract
Aryl radicals play a pivotal role as reactive intermediates in chemical synthesis, commonly arising from aryl halides and aryl diazo compounds. Expanding the repertoire of sources for aryl radical generation to include abundant and stable organoboron reagents would significantly advance radical chemistry and broaden their reactivity profile. While traditional approaches utilize stoichiometric oxidants or photocatalysis to generate aryl radicals from these reagents, electrochemical conditions have been largely underexplored. Through rigorous mechanistic investigations, we identified fundamental challenges hindering aryl radical generation. In addition to the high oxidation potentials of aromatic organoboron compounds, electrode passivation through radical grafting, homocoupling of aryl radicals, and decomposition issues were identified. We demonstrate that pulsed electrosynthesis enables selective and efficient aryl radical generation by mitigating the fundamental challenges. Our discoveries facilitated the development of the first electrochemical conversion of aryl potassium trifluoroborate salts into aryl C-P bonds. This sustainable and straightforward oxidative electrochemical approach exhibited a broad substrate scope, accommodating various heterocycles and aryl chlorides, typical substrates in transition-metal catalyzed cross-coupling reactions. Furthermore, we extended this methodology to form aryl C-Se, C-Te, and C-S bonds, showcasing its versatility and potential in bond formation processes.
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Affiliation(s)
- Maxime Boudjelel
- Department of Chemistry, Northwestern University, 2145 N Sheridan Road, Evanston, IL 60208, USA
| | - Jessica Zhong
- Department of Chemistry, Northwestern University, 2145 N Sheridan Road, Evanston, IL 60208, USA
| | - Lorenzo Ballerini
- Department of Chemistry, Northwestern University, 2145 N Sheridan Road, Evanston, IL 60208, USA
| | - Ian Vanswearingen
- Department of Chemistry, Northwestern University, 2145 N Sheridan Road, Evanston, IL 60208, USA
| | - Rossul Al-Dhufari
- Department of Chemistry, Northwestern University, 2145 N Sheridan Road, Evanston, IL 60208, USA
| | - Christian A Malapit
- Department of Chemistry, Northwestern University, 2145 N Sheridan Road, Evanston, IL 60208, USA
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5
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Halford-McGuff JM, Varga M, Cordes DB, McKay AP, Watson AJB. Modular Synthesis of Complex Benzoxaboraheterocycles through Chelation-Assisted Rh-Catalyzed [2 + 2 + 2] Cycloaddition. ACS Catal 2024; 14:1846-1854. [PMID: 38327642 PMCID: PMC10845118 DOI: 10.1021/acscatal.3c05766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 02/09/2024]
Abstract
Benzoxaboraheterocycles (BOBs) are moieties of increasing interest in the pharmaceutical industry; however, the synthesis of these compounds is often difficult or impractical due to the sensitivity of the boron moiety, the requirement for metalation-borylation protocols, and lengthy syntheses. We report a straightforward, modular approach that enables access to complex examples of the BOB framework through a Rh-catalyzed [2 + 2 + 2] cycloaddition using MIDA-protected alkyne boronic acids. The key to the development of this methodology was overcoming the steric barrier to catalysis by leveraging chelation assistance. We show the utility of the method through synthesis of a broad range of BOB scaffolds, mechanistic information on the chelation effect, intramolecular alcohol-assisted BMIDA hydrolysis, and linear/cyclic BOB limits as well as comparative binding affinities of the product BOB frameworks for ribose-derived biomolecules.
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Affiliation(s)
- John M. Halford-McGuff
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K.
| | - Marek Varga
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K.
| | - David B. Cordes
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K.
| | - Aidan P. McKay
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K.
| | - Allan J. B. Watson
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K.
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6
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Hao K, Li D, Fu D, Zou P, Xie S, Lan Y, Chen Y. Metal-Free 1,3-Boronate Rearrangement to Ketones Driven by Visible Light. Angew Chem Int Ed Engl 2024; 63:e202316481. [PMID: 38063138 DOI: 10.1002/anie.202316481] [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: 10/31/2023] [Indexed: 12/21/2023]
Abstract
Boronate rearrangements, such as the Matteson and Petasis reactions, are valuable metal-free reactions for the transfer of the carbo group on boron to intramolecular electrophilic sites. However, only highly reactive electrophiles are suitable, and ketones are too inactive for those boronate rearrangements due to the high energy barriers. We disclose here the 1,3-boronate rearrangement to ketones, for which a high energy barrier (44.9 kcal/mol) is prohibitory for thermal reactions in the ground state. The reaction is enabled by the key keto-enol-boronate bidentate complex formation in situ, which absorbs visible light to reach the excited state for the chemoselective 1,3-boronate rearrangement to ketones. Experimental and computational investigations exclude free radical intermediates from organoboronates. The aryl, alkenyl, and alkyl boronic acids react with various 1,3-diketones driven by visible light irradiation to construct structurally diverse β-keto tertiary alcohols under metal-free conditions. The reaction demonstrates substrate diversity with 58 examples, yields up to 98 %, and it is suitable for gram-scale synthesis.
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Affiliation(s)
- Kejia Hao
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Defang Li
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
- School of Physical Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai, 201210, China
| | - Dongmin Fu
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan, 450001, China
| | - Peng Zou
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Shasha Xie
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Yu Lan
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan, 450001, China
- School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing, 400030, China
| | - Yiyun Chen
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
- School of Physical Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai, 201210, China
- School of Chemistry and Material Sciences, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
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7
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Youshaw C, Yang MH, Gogoi AR, Rentería-Gómez A, Liu L, Morehead LM, Gutierrez O. Iron-Catalyzed Enantioselective Multicomponent Cross-Couplings of α-Boryl Radicals. Org Lett 2023; 25:8320-8325. [PMID: 37956189 PMCID: PMC10863393 DOI: 10.1021/acs.orglett.3c03387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/03/2023] [Accepted: 11/07/2023] [Indexed: 11/15/2023]
Abstract
Despite recent interest in the development of iron-catalyzed transformations, methods that use iron-based catalysts capable of controlling the enantioselectivity in carbon-carbon cross-couplings are underdeveloped. Herein, we report a practical and simple protocol that uses commercially available and expensive iron salts in combination with chiral bisphosphine ligands to enable the regio- and enantioselective (up to 91:9) multicomponent cross-coupling of vinyl boronates, (fluoro)alkyl halides, and Grignard reagents. Preliminary mechanistic studies are consistent with rapid formation of an α-boryl radical followed by reversible radical addition to monoaryl bisphosphine-Fe(II) and subsequent enantioselective inner-sphere reductive elimination. From a broader perspective, this work provides a blueprint to develop asymmetric Fe-catalyzed multicomponent cross-couplings via the use of alkenes as linchpins to translocate alkyl radicals, modify their steric and electronic properties, and induce stereocontrol.
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Affiliation(s)
| | | | | | | | - Lei Liu
- Department of Chemistry, Texas A&M University, College
Station, Texas 77843, United States
| | - Lukas M. Morehead
- 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
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8
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Brals J, McGuire TM, Watson AJB. A Chemoselective Polarity-Mismatched Photocatalytic C(sp 3 )-C(sp 2 ) Cross-Coupling Enabled by Synergistic Boron Activation. Angew Chem Int Ed Engl 2023; 62:e202310462. [PMID: 37622419 PMCID: PMC10952440 DOI: 10.1002/anie.202310462] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/21/2023] [Accepted: 08/24/2023] [Indexed: 08/26/2023]
Abstract
We report the development of a C(sp3 )-C(sp2 ) coupling reaction using styrene boronic acids and redox-active esters under photoredox catalysis. The reaction proceeds through an unusual polarity-mismatched radical addition mechanism that is orthogonal to established processes. Synergistic activation of the radical precursor and organoboron are critical mechanistic events. Activation of an N-hydroxyphthalimide (NHPI) ester by coordination to boron enables electron transfer, with decomposition leading to a nucleofuge rebound, activating the organoboron to radical addition. The unique mechanism enables chemoselective coupling of styrene boronic acids in the presence of other alkene radical acceptors. The scope and limitations of the reaction, and a detailed mechanistic investigation are presented.
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Affiliation(s)
- Jeremy Brals
- EaStCHEMSchool of ChemistryUniversity of St AndrewsPurdie Building, North HaughSt AndrewsKY16 9STUK
| | - Thomas M. McGuire
- AstraZenecaDarwin Building, Unit 310Cambridge Science Park, Milton RoadCambridgeCB4 0WGUK
| | - Allan J. B. Watson
- EaStCHEMSchool of ChemistryUniversity of St AndrewsPurdie Building, North HaughSt AndrewsKY16 9STUK
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9
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Zähringer TJB, Wienhold M, Gilmour R, Kerzig C. Direct Observation of Triplet States in the Isomerization of Alkenylboronates by Energy Transfer Catalysis. J Am Chem Soc 2023; 145:21576-21586. [PMID: 37729087 DOI: 10.1021/jacs.3c07678] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Alkenylboronates are versatile building blocks for stereocontrolled synthesis owing to the traceless nature of the boron group that can be leveraged to achieve highly selective geometric isomerization. Using thioxanthone as an inexpensive photocatalyst, the photoisomerization of these species continues to provide an expansive platform for stereodivergent synthesis, particularly in the construction of bioactive polyenes. Although mechanistic investigations are consistent with light-driven energy transfer, direct experimental evidence remains conspicuously absent. Herein, we report a rigorous mechanistic investigation using two widely used alkenylboronates alongside relevant reference compounds. Through the combination of irradiation experiments, transient absorption spectroscopic studies, kinetic modeling, and DFT calculations with all isomers of the model compounds, it has been possible to unequivocally detect and characterize the perpendicular triplet generated by energy transfer. Our results serve not only as a blueprint for mechanistic studies that are challenging with organic sensitizers, but these guidelines delineated have also enabled the development of more sustainable reaction conditions: for the first time, efficient organocatalytic isomerization under sunlight irradiation has become feasible.
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Affiliation(s)
- Till J B Zähringer
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Max Wienhold
- Organisch-Chemisches Institut,Westfälische Wilhelms-Universität Münster, Correnstraβe 36, 48149 Münster, Germany
| | - Ryan Gilmour
- Organisch-Chemisches Institut,Westfälische Wilhelms-Universität Münster, Correnstraβe 36, 48149 Münster, Germany
- Cells in Motion (CiM) Interfaculty Center, Röntgenstraβe 16, 48149 Münster, Germany
| | - Christoph Kerzig
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
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10
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LaPorte AJ, Feldner JE, Spies JC, Maher TJ, Burke MD. MIDA- and TIDA-Boronates Stabilize α-Radicals Through B-N Hyperconjugation. Angew Chem Int Ed Engl 2023; 62:e202309566. [PMID: 37540542 DOI: 10.1002/anie.202309566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/05/2023]
Abstract
Multifunctional organoboron compounds increasingly enable the simple generation of complex, Csp3 -rich small molecules. The ability of boron-containing functional groups to modify the reactivity of α-radicals has also enabled a myriad of chemical reactions. Boronic esters with vacant p-orbitals have a significant stabilizing effect on α-radicals due to delocalization of spin density into the empty orbital. The effect of coordinatively saturated derivatives, such as N-methyliminodiacetic acid (MIDA) boronates and counterparts, remains less clear. Herein, we demonstrate that coordinatively saturated MIDA and TIDA boronates stabilize secondary alkyl α-radicals via σB-N hyperconjugation in a manner that allows site-selective C-H bromination. DFT calculated radical stabilization energies and spin density maps as well as LED NMR kinetic analysis of photochemical bromination rates of different boronic esters further these findings. This work clarifies that the α-radical stabilizing effect of boronic esters does not only proceed via delocalization of radical character into vacant boron p-orbitals, but that hyperconjugation of tetrahedral boron-containing functional groups and their ligand electron delocalizing ability also play a critical role. These findings establish boron ligands as a useful dial for tuning reactivity at the α-carbon.
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Affiliation(s)
- Antonio J LaPorte
- Department of Chemistry, University of Illinois, Urbana, IL, 61820, USA
| | - Jack E Feldner
- Department of Chemistry, University of Illinois, Urbana, IL, 61820, USA
| | - Jan C Spies
- Department of Chemistry, University of Illinois, Urbana, IL, 61820, USA
| | - Tom J Maher
- Department of Chemistry, University of Illinois, Urbana, IL, 61820, USA
| | - Martin D Burke
- Department of Chemistry, University of Illinois, Urbana, IL, 61820, USA
- Carle Illinois College of Medicine, University of Illinois, Urbana, IL, 61820, USA
- Department of Biochemistry, University of Illinois, Urbana, IL, 61820, USA
- Arnold and Mable Beckman Institute, University of Illinois, Urbana, IL, 61820, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, 61820, USA
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11
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Xie KA, Bednarova E, Joe CL, Lin C, Sherwood TC, Simmons EM, Lainhart BC, Rovis T. Orange Light-Driven C(sp 2)-C(sp 3) Cross-Coupling via Spin-Forbidden Ir(III) Metallaphotoredox Catalysis. J Am Chem Soc 2023; 145:19925-19931. [PMID: 37642382 DOI: 10.1021/jacs.3c06285] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
We report the development and characterization of a library of Ir(III) photocatalysts capable of undergoing spin-forbidden excitation (SFE) under orange light irradiation (595 nm). These catalysts were successfully applied to the construction of synthetically valuable C(sp2)-C(sp3) bonds inaccessible with existing methods of low-energy light-driven dual nickel/photoredox catalysis, demonstrating the synthetic utility of this photocatalyst family. The photocatalysts are capable of accessing both oxidatively and reductively activated coupling partners, illustrated through deaminative arylation and potassium alkyl trifluoroborate cross-coupling reactions with aryl halides. We demonstrate diverse substrate scopes of both cross-coupling paradigms under mild conditions in the first example of low-energy light-driven C(sp2)-C(sp3) metallaphotoredox coupling.
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Affiliation(s)
- Katherine A Xie
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Eva Bednarova
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Candice L Joe
- Chemical Process Development, Bristol Myers Squibb, 1 Squibb Drive, New Brunswick, New Jersey 08903, United States
| | - Chenxi Lin
- Department of Chemistry, Barnard College, New York, New York 10027, United States
| | - Trevor C Sherwood
- Small Molecule Drug Discovery, Bristol Myers Squibb, Princeton, New Jersey 08543, United States
| | - Eric M Simmons
- Chemical Process Development, Bristol Myers Squibb, 1 Squibb Drive, New Brunswick, New Jersey 08903, United States
| | - Brendan C Lainhart
- Chemical Process Development, Bristol Myers Squibb, 1 Squibb Drive, New Brunswick, New Jersey 08903, United States
| | - Tomislav Rovis
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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12
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Marotta A, Fang H, Adams CE, Sun Marcus K, Daniliuc CG, Molloy JJ. Direct Light-Enabled Access to α-Boryl Radicals: Application in the Stereodivergent Synthesis of Allyl Boronic Esters. Angew Chem Int Ed Engl 2023; 62:e202307540. [PMID: 37326432 DOI: 10.1002/anie.202307540] [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: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 06/17/2023]
Abstract
Operationally simple strategies to assemble boron containing organic frameworks are highly enabling in organic synthesis. While conventional retrosynthetic logic has engendered many platforms focusing on the direct formation of C-B bonds, α-boryl radicals have recently reemerged as versatile open-shell alternatives to access organoborons via adjacent C-C bond formation. Direct light-enabled α-activation is currently contingent on photo- or transition metal-catalysis activation to efficiently generate radical species. Here, we disclose a facile activation of α-halo boronic esters using only visible light and a simple Lewis base to enable homolytic scission. Intermolecular addition to styrenes facilitates the rapid construction of highly versatile E-allylic boronic esters. The simplicity of activation permits the strategic merger of this construct with selective energy transfer catalysis to enable the complimentary stereodivergent synthesis of Z-allylic boronic esters.
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Affiliation(s)
- Alessandro Marotta
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
| | - Hao Fang
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
| | - Callum E Adams
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Kailey Sun Marcus
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - John J Molloy
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
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13
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Dong Y, Meng X, Gnawali G, Chang M, Wang W. Photoredox Catalytic Installation of an Alkyl/Aryl Side Chain and Deuterium into ( S)-Methyleneoxazolidinone: Synthesis of Enantioenriched α-Deuterated α-Amino Acid Derivatives. Org Lett 2023. [PMID: 37326373 DOI: 10.1021/acs.orglett.3c01760] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
A photoredox catalytic asymmetric method has been established for the installation of both aliphatic and aromatic side chains and the introduction of deuterium into the chiral methyleneoxazolidinone simultaneously. Efficient coupling of readily available boronic acids with the chiral auxiliary delivers structurally diverse α-deuterated α-amino acid derivatives with a high level of diastereoselectivity and deuteration.
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Affiliation(s)
- Yue Dong
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona 85721, United States
| | - Xiang Meng
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona 85721, United States
| | - Giri Gnawali
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona 85721, United States
| | - Mengyang Chang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Wei Wang
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona 85721, United States
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- BIO5 Institute, University of Arizona, Tucson, Arizona 85721, United States
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14
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Bastick KA, Watson AJB. Pd-Catalyzed Organometallic-Free Homologation of Arylboronic Acids Enabled by Chemoselective Transmetalation. ACS Catal 2023; 13:7013-7018. [PMID: 37229436 PMCID: PMC10204063 DOI: 10.1021/acscatal.3c00921] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/28/2023] [Indexed: 05/27/2023]
Abstract
A Pd-catalyzed homologation of arylboronic acids is reported. Halomethylboronic acid pinacol esters (Bpin) undergo a remarkably facile, yet rare, oxidative addition enabled by an α-boryl effect. Simultaneous chemoselective transmetalation allows use of these metalloid reagents for formal C1 insertion to deliver benzyl Bpin products without the requirement for stoichiometric organometallic reagents. The utility of the process is demonstrated by stepwise C(sp3)-C(sp2) cross-coupling of the boronic ester products into diarylmethane pharmacophores and electrophile/nucleophile chemoselective cross-coupling. Control experiments that demonstrate the reactivity enhancement provided by the α-boryl effect are provided, along with a description of the limitations of the formal homologation process.
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15
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Kong D, Zhang M, Zhang Y, Yu Z, Cao H, Wu J. Photocatalyzed regioselective hydrosilylation for the divergent synthesis of geminal and vicinal borosilanes. Nat Commun 2023; 14:2525. [PMID: 37130840 PMCID: PMC10154379 DOI: 10.1038/s41467-023-38224-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 04/21/2023] [Indexed: 05/04/2023] Open
Abstract
Geminal and vicinal borosilanes are useful building blocks in synthetic chemistry and material science. Hydrosilylation/hydroborylation of unsaturated systems offer expedient access to these motifs. In contrast to the well-established transition-metal-catalyzed methods, radical approaches are rarely explored. Herein we report the synthesis of geminal borosilanes from α-selective hydrosilylation of alkenyl boronates via photoinduced hydrogen atom transfer (HAT) catalysis. Mechanistic studies implicate that the α-selectivity originates from a kinetically favored radical addition and an energetically favored HAT process. We further demonstrate selective synthesis of vicinal borosilanes through hydrosilylation of allyl boronates via 1,2-boron radical migration. These strategies exhibit broad scopes across primary, secondary, and tertiary silanes and various boron compounds. The synthetic utility is evidenced by access to multi-borosilanes in a diverse fashion and scaling up by continuous-flow synthesis.
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Affiliation(s)
- Degong Kong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Republic of Singapore
- School of Chemical Engineering & Technology, Harbin Institute of Technology, Harbin, 150001, China
| | - Muliang Zhang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Republic of Singapore
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China
| | - Yuchao Zhang
- Institute of Basic Medicine and Cancer (IBMC), Cancer Hospital of the University of Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, China
| | - Zhenyang Yu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Republic of Singapore
| | - Hui Cao
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Republic of Singapore.
| | - Jie Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Republic of Singapore.
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16
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M T, Callum. Emerging radical rearrangement reactions: The 1,2-boron shift. GREEN SYNTHESIS AND CATALYSIS 2022. [DOI: 10.1016/j.gresc.2022.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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