1
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Ruyet L, Roblick C, Häfliger J, Wang ZX, Stoffels TJ, Daniliuc CG, Gilmour R. Catalytic Ring Expanding Difluorination: An Enantioselective Platform to Access β,β-Difluorinated Carbocycles. Angew Chem Int Ed Engl 2024; 63:e202403957. [PMID: 38482736 DOI: 10.1002/anie.202403957] [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: 02/26/2024] [Indexed: 04/11/2024]
Abstract
Cyclic β,β-difluoro-carbonyl compounds have a venerable history as drug discovery leads, but limitations in the synthesis arsenal continue to impede chemical space exploration. This challenge is particularly acute in the arena of fluorinated medium rings where installing the difluoromethylene unit subtly alters the ring conformation by expanding the internal angle (∠C-CF2-C>∠C-CH2-C): this provides a handle to modulate physicochemistry (e.g. pKa). To reconcile this disparity, a highly modular ring expansion has been devised that leverages simple α,β-unsaturated esters and amides, and processes them to one-carbon homologated rings with concomitant geminal difluorination (6 to 10 membered rings, up to 95 % yield). This process is a rare example of the formal difluorination of an internal alkene and is enabled by sequential I(III)-enabled O-activation. Validation of enantioselective catalysis in the generation of unprecedented medium ring scaffolds is reported (up to 93 : 7 e.r.) together with X-ray structural analyses and product derivatization.
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Affiliation(s)
- Louise Ruyet
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Christoph Roblick
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Joel Häfliger
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Zi-Xuan Wang
- University of Münster, Institute for Organic Chemistry, Corrensstraße 36, 48149, Münster, Germany
| | - Tobias Jürgen Stoffels
- 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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2
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Elsherbini M, Moran WJ. Toward a General Protocol for Catalytic Oxidative Transformations Using Electrochemically Generated Hypervalent Iodine Species. J Org Chem 2023; 88:1424-1433. [PMID: 36689352 PMCID: PMC9903329 DOI: 10.1021/acs.joc.2c02309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A simple catalytic electrosynthetic protocol for oxidative transformations mediated by hypervalent iodine reagents has been developed. In this protocol, electricity drives the iodine(I)/iodine(III) catalytic cycle enabling catalysis with in situ generated hypervalent iodine species, thereby eliminating chemical oxidants and the inevitable chemical waste associated with their mode of action. In addition, no added electrolytic salts are needed in this process. The developed method has been validated using two different hypervalent iodine-mediated transformations: (i) the oxidative cyclization of N-allylic and N-homoallylic amides to the corresponding dihydrooxazole and dihydro-1,3-oxazine derivatives, respectively, and (ii) the α-tosyloxylation of ketones. Both reactions proceeded smoothly under the developed catalytic electrosynthetic conditions without reoptimization, featuring a wide substrate scope and excellent functional group tolerance. In addition, scale-up to gram-scale and catalyst recovery were easily achieved maintaining the high efficiency of the process.
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3
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Yu YJ, Schäfer M, Daniliuc CG, Gilmour R. Catalytic, Regioselective 1,4-Fluorodifunctionalization of Dienes. Angew Chem Int Ed Engl 2023; 62:e202214906. [PMID: 36345795 PMCID: PMC10107283 DOI: 10.1002/anie.202214906] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Indexed: 11/09/2022]
Abstract
A catalysis-based regioselective 1,4-fluorofunctionalization of trifluoromethyl substituted 1,3-dienes has been developed to access compact, highly functionalized products. The process allows E,Z-mixed dienes to be processed to a single E-alkene isomer, and leverages an inexpensive and operationally convenient I(I)/I(III) catalysis platform. The first example of catalytic 1,4-difluorination is disclosed and subsequently evolved to enable 1,4-hetero-difunctionalization, which allows δ-fluoro-alcohol and amine derivatives to be forged in a single operation. The protocol is compatible with a variety of nucleophiles including fluoride, nitriles, carboxylic acids, alcohols and even water thereby allowing highly functionalized products, with a stereocenter bearing both C(sp3 )-F and C(sp3 )-CF3 groups, to be generated rapidly. Scalability (up to 3 mmol), and facile post-reaction modifications are demonstrated to underscore the utility of the method in expanding organofluorine chemical space.
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Affiliation(s)
- You-Jie Yu
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149, Münster, Germany
| | - Michael Schäfer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149, Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149, Münster, Germany
| | - Ryan Gilmour
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149, Münster, Germany
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4
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Berger M, Lenhard MS, Waldvogel SR. Para-Fluorination of Anilides Using Electrochemically Generated Hypervalent Iodoarenes. Chemistry 2022; 28:e202201029. [PMID: 35510825 PMCID: PMC9401020 DOI: 10.1002/chem.202201029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Indexed: 11/23/2022]
Abstract
The para-selective fluorination reaction of anilides using electrochemically generated hypervalent ArIF2 is reported, with Et3 N ⋅ 5HF serving as fluoride source and as supporting electrolyte. This electrochemical reaction is characterized by a simple set-up, easy scalability and affords a broad variety of fluorinated anilides from easily accessible anilides in good yields up to 86 %.
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Affiliation(s)
- Michael Berger
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Marola S. Lenhard
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Siegfried R. Waldvogel
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
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5
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Sokolovs I, Mohebbati N, Francke R, Suna E. Electrochemical Generation of Hypervalent Bromine(III) Compounds. Angew Chem Int Ed Engl 2021; 60:15832-15837. [PMID: 33894098 PMCID: PMC8362160 DOI: 10.1002/anie.202104677] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Indexed: 11/09/2022]
Abstract
In sharp contrast to hypervalent iodine(III) compounds, the isoelectronic bromine(III) counterparts have been little studied to date. This knowledge gap is mainly attributed to the difficult-to-control reactivity of λ3 -bromanes as well as to their challenging preparation from the highly toxic and corrosive BrF3 precursor. In this context, we present a straightforward and scalable approach to chelation-stabilized λ3 -bromanes by anodic oxidation of parent aryl bromides possessing two coordinating hexafluoro-2-hydroxypropanyl substituents. A series of para-substituted λ3 -bromanes with remarkably high redox potentials spanning a range from 1.86 V to 2.60 V vs. Ag/AgNO3 was synthesized by the electrochemical method. We demonstrate that the intrinsic reactivity of the bench-stable bromine(III) species can be unlocked by addition of a Lewis or a Brønsted acid. The synthetic utility of the λ3 -bromane activation is exemplified by oxidative C-C, C-N, and C-O bond forming reactions.
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Affiliation(s)
- Igors Sokolovs
- Latvian Institute of Organic SynthesisAizkraukles 211006RigaLatvia
- Institute of ChemistryRostock UniversityAlbert-Einstein-Str. 3a18059RostockGermany
| | - Nayereh Mohebbati
- Leibniz Institute for CatalysisAlbert-Einstein-Str. 29a18059RostockGermany
- Institute of ChemistryRostock UniversityAlbert-Einstein-Str. 3a18059RostockGermany
| | - Robert Francke
- Leibniz Institute for CatalysisAlbert-Einstein-Str. 29a18059RostockGermany
- Institute of ChemistryRostock UniversityAlbert-Einstein-Str. 3a18059RostockGermany
| | - Edgars Suna
- Latvian Institute of Organic SynthesisAizkraukles 211006RigaLatvia
- Faculty of ChemistryUniversity of LatviaJelgavas 11004RigaLatvia
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6
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Sokolovs I, Mohebbati N, Francke R, Suna E. Electrochemical Generation of Hypervalent Bromine(III) Compounds. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Igors Sokolovs
- Latvian Institute of Organic Synthesis Aizkraukles 21 1006 Riga Latvia
- Institute of Chemistry Rostock University Albert-Einstein-Str. 3a 18059 Rostock Germany
| | - Nayereh Mohebbati
- Leibniz Institute for Catalysis Albert-Einstein-Str. 29a 18059 Rostock Germany
- Institute of Chemistry Rostock University Albert-Einstein-Str. 3a 18059 Rostock Germany
| | - Robert Francke
- Leibniz Institute for Catalysis Albert-Einstein-Str. 29a 18059 Rostock Germany
- Institute of Chemistry Rostock University Albert-Einstein-Str. 3a 18059 Rostock Germany
| | - Edgars Suna
- Latvian Institute of Organic Synthesis Aizkraukles 21 1006 Riga Latvia
- Faculty of Chemistry University of Latvia Jelgavas 1 1004 Riga Latvia
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7
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Neufeld J, Stünkel T, Mück‐Lichtenfeld C, Daniliuc CG, Gilmour R. Synthese von trifluorierten Tetralinen durch I(I)/I(III)‐katalysierte Ringexpansion: programmieren von Konformationen über [CH
2
CH
2
] → [CF
2
CHF] Isosterismus. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102222] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Jessica Neufeld
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Germany
| | - Timo Stünkel
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Germany
| | - Christian Mück‐Lichtenfeld
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Germany
| | - Ryan Gilmour
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Germany
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8
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Neufeld J, Stünkel T, Mück‐Lichtenfeld C, Daniliuc CG, Gilmour R. Trifluorinated Tetralins via I(I)/I(III)-Catalysed Ring Expansion: Programming Conformation by [CH 2 CH 2 ] → [CF 2 CHF] Isosterism. Angew Chem Int Ed Engl 2021; 60:13647-13651. [PMID: 33721384 PMCID: PMC8251640 DOI: 10.1002/anie.202102222] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/12/2021] [Indexed: 12/15/2022]
Abstract
Saturated, fluorinated carbocycles are emerging as important modules for contemporary drug discovery. To expand the current portfolio, the synthesis of novel trifluorinated tetralins has been achieved. Fluorinated methyleneindanes serve as convenient precursors and undergo efficient difluorinative ring expansion with in situ generated p-TolIF2 (>20 examples, up to >95 %). A range of diverse substituents are tolerated under standard catalysis conditions and this is interrogated by Hammett analysis. X-ray analysis indicates a preference for the CH-F bond to occupy a pseudo-axial orientation, consistent with stabilising σC-H →σC-F * interactions. The replacement of the symmetric [CH2 -CH2 ] motif by [CF2 -CHF] removes the conformational degeneracy intrinsic to the parent tetralin scaffold leading to a predictable half-chair. The conformational behavior of this novel structural balance has been investigated by computational analysis and is consistent with stereoelectronic theory.
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Affiliation(s)
- Jessica Neufeld
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - Timo Stünkel
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - Christian Mück‐Lichtenfeld
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - Constantin G. Daniliuc
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - Ryan Gilmour
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
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9
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Heard DM, Doobary S, Lennox AJJ. 3D Printed Reactionware for Synthetic Electrochemistry with Hydrogen Fluoride Reagents. ChemElectroChem 2021. [DOI: 10.1002/celc.202100496] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- David M. Heard
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS
| | - Sayad Doobary
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS
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10
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Strehl J, Abraham ML, Hilt G. Lineare gepaarte Elektrolyse – Realisierung von 200 % Stromausbeute in stöchiometrischen Umsetzungen – die elektrochemische Bromierung von Alkenen. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Julia Strehl
- Institut für Chemie Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
| | - Marvin L. Abraham
- Institut für Chemie Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
| | - Gerhard Hilt
- Institut für Chemie Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
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11
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Strehl J, Abraham ML, Hilt G. Linear Paired Electrolysis-Realising 200 % Current Efficiency for Stoichiometric Transformations-The Electrochemical Bromination of Alkenes. Angew Chem Int Ed Engl 2021; 60:9996-10000. [PMID: 33656769 PMCID: PMC8251945 DOI: 10.1002/anie.202016413] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/15/2021] [Indexed: 11/11/2022]
Abstract
The generation of bromine by oxidation of bromide anions at the anode and reduction of molecular oxygen at the cathode to hydrogen peroxide resulted in the overall formation of two molecules of Br2 (=four electron oxidation) by passing just two electrons through the solution. The bromine was used for the bromination of alkenes and thereby a linear paired electrolysis was attained which resulted in current efficencies of up to 200 %. Also, the diiodination of cyclohexene as well as the electrophilic aromatic bromination of an electron‐rich arene were realised both in 168 % current efficiencies.
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Affiliation(s)
- Julia Strehl
- Institut für Chemie, Universität Oldenburg, Carl-von-Ossietzky-Strasse 9-11, 26111, Oldenburg, Germany
| | - Marvin L Abraham
- Institut für Chemie, Universität Oldenburg, Carl-von-Ossietzky-Strasse 9-11, 26111, Oldenburg, Germany
| | - Gerhard Hilt
- Institut für Chemie, Universität Oldenburg, Carl-von-Ossietzky-Strasse 9-11, 26111, Oldenburg, Germany
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12
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Meyer S, Häfliger J, Schäfer M, Molloy JJ, Daniliuc CG, Gilmour R. A Chiral Pentafluorinated Isopropyl Group via Iodine(I)/(III) Catalysis. Angew Chem Int Ed Engl 2021; 60:6430-6434. [PMID: 33427355 PMCID: PMC7986799 DOI: 10.1002/anie.202015946] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/08/2021] [Indexed: 12/15/2022]
Abstract
An I(I)/(III) catalysis strategy to construct an enantioenriched fluorinated isostere of the i Pr group is reported. The difluorination of readily accessible α-CF3 -styrenes is enabled by the in situ generation of a chiral ArIF2 species to forge a stereocentre with the substituents F, CH2 F and CF3 (up to 95 %, >20:1 vicinal:geminal difluorination). The replacement of the metabolically labile benzylic proton results in a highly preorganised scaffold as was determined by X-ray crystallography (π→σ* and stereoelectronic gauche σ→σ* interactions). A process of catalyst editing is disclosed in which preliminary validation of enantioselectivity is placed on a structural foundation.
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Affiliation(s)
- Stephanie Meyer
- Organisch Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - Joel Häfliger
- Organisch Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - Michael Schäfer
- Organisch Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - John J. Molloy
- Organisch Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - Constantin G. Daniliuc
- Organisch Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
| | - Ryan Gilmour
- Organisch Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstraße 3648149MünsterGermany
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13
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Meyer S, Häfliger J, Schäfer M, Molloy JJ, Daniliuc CG, Gilmour R. Eine chirale pentafluorierte Isopropylgruppe durch Iod(I)/(III)‐Katalyse. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015946] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Stephanie Meyer
- Organisch Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Deutschland
| | - Joel Häfliger
- Organisch Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Deutschland
| | - Michael Schäfer
- Organisch Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Deutschland
| | - John J. Molloy
- Organisch Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Deutschland
| | - Constantin G. Daniliuc
- Organisch Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Deutschland
| | - Ryan Gilmour
- Organisch Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Deutschland
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14
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Elsherbini M, Huynh F, Dunbabin A, Allemann RK, Wirth T. Selective Hydroboration-Oxidation of Terminal Alkenes under Flow Conditions. Chemistry 2020; 26:11423-11425. [PMID: 32329919 PMCID: PMC7540268 DOI: 10.1002/chem.202001650] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Indexed: 11/20/2022]
Abstract
An efficient flow process for the selective hydroboration and oxidation of different alkenes using 9-borabicyclo(3.3.1)nonane (9-BBN) allows facile conversion in high productivity (1.4 g h-1 ) of amorpha-4,11-diene to the corresponding alcohol, which is an advanced intermediate in the synthesis of the antimalarial drug artemisinin. The in situ reaction of borane and 1,5-cyclooctadiene using a simple flow generator proved to be a cost efficient solution for the generation of 9-BBN.
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Affiliation(s)
- Mohamed Elsherbini
- School of ChemistryCardiff UniversityMain Building, Park PlaceCardiffCF10 3ATUK
| | - Florence Huynh
- School of ChemistryCardiff UniversityMain Building, Park PlaceCardiffCF10 3ATUK
| | - Alice Dunbabin
- School of ChemistryCardiff UniversityMain Building, Park PlaceCardiffCF10 3ATUK
| | - Rudolf K. Allemann
- School of ChemistryCardiff UniversityMain Building, Park PlaceCardiffCF10 3ATUK
| | - Thomas Wirth
- School of ChemistryCardiff UniversityMain Building, Park PlaceCardiffCF10 3ATUK
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15
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Wang C, Tu Y, Ma D, Bolm C. Photocatalytic Fluoro Sulfoximidations of Styrenes. Angew Chem Int Ed Engl 2020; 59:14134-14137. [PMID: 32415689 PMCID: PMC7496861 DOI: 10.1002/anie.202005844] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/15/2020] [Indexed: 12/27/2022]
Abstract
Reactions of difluoroiodotoluene with NH‐sulfoximines provide new hypervalent iodine(III) reagents, which photocatalytically transfer a fluoro and a sulfoximidoyl group onto styrenes with high regioselectivity. The substrate scope is broad with respect to both sulfoximines and olefins. Following an operationally simple protocol, a large library of fluorine‐containing N‐functionalized sulfoximines can be accessed. Results from mechanistic investigations revealed the importance of radical intermediates.
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Affiliation(s)
- Chenyang Wang
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Yongliang Tu
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Ding Ma
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Carsten Bolm
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
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16
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Wang C, Tu Y, Ma D, Bolm C. Photocatalytic Fluoro Sulfoximidations of Styrenes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005844] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Chenyang Wang
- Institute of Organic Chemistry RWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Yongliang Tu
- Institute of Organic Chemistry RWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Ding Ma
- Institute of Organic Chemistry RWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Carsten Bolm
- Institute of Organic Chemistry RWTH Aachen University Landoltweg 1 52074 Aachen Germany
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17
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O'Hagan D. Polar Organofluorine Substituents: Multivicinal Fluorines on Alkyl Chains and Alicyclic Rings. Chemistry 2020; 26:7981-7997. [PMID: 32083392 DOI: 10.1002/chem.202000178] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/20/2020] [Indexed: 12/12/2022]
Abstract
This Review outlines the progression, primarily of our own work, but with important contributions from other labs, on the synthesis and properties of multiple vicinally fluorinated alkyl chains and rings. Chain conformations of individual diastereoisomers with -CHF- at adjacent carbons are influenced by stereoelectronic factors associated with the polar C-F bond and the polarised geminal hydrogens. Generally, the chain will prefer a conformation which acts to minimise overall molecular polarity, and where the C-F bonds orient away from each other. However, when vicinal fluorine atoms are positioned on a ring then conformations are more constrained. The ring will adopt optimal conformations such as a chair in cyclohexane and then C-F bonds can be introduced with a stereochemistry that forces parallel (axial) orientations. In the case of cyclohexane, 1,3-diaxial arrangements of C-F bonds impart considerable polarity to the ring, resulting in an electronegative 'fluorine face' and an electropositive 'hydrogen face'. For all-syn 1,2,3,4,5,6-hexafluorocyclohexane, this arrangement generates an unusually polar aliphatic ring system. Most recently the concept has been extended to the preparation of all-syn 1,2,3-trifluorocyclopropanes, a rigid ring system with fluorine atoms on one face and hydrogens on the other. Lipophilicity Log P values of such compounds indicate that they are significantly more polar than their parent alicyclic hydrocarbons and give some positive indication for a future role of such substituents in medicinal chemistry. Expanding to such a role will require access to improved synthesis methods to these motifs and consequently access to a broader a range of building blocks, however some exciting new methods have emerged recently and these are briefly reviewed.
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Affiliation(s)
- David O'Hagan
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK
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