| 1. |
- Devaraj, Karthik, et al.
(author)
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Arynes and Their Precursors from Arylboronic Acids via Catalytic C-H Silylation
- 2019
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In: Journal of Organic Chemistry. - : AMER CHEMICAL SOC. - 0022-3263 .- 1520-6904. ; 84:9, s. 5863-5871
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Journal article (peer-reviewed)abstract
- A new, operationally simple approach is presented to access arynes and their fluoride-activated precursors based on Ru-catalyzed C-H silylation of arylboronates. Chromatographic purification may be deferred until after aryne capture, rendering the arylboronates de facto precursors. Access to various new arynes and their derivatives is demonstrated, including, for the first time, those based on a 2,3-carbazolyne and 2,3-fluorenyne core, which pave the way for novel derivatizations of motifs relevant to materials chemistry.
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| 2. |
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| 3. |
- Ingner, Fredric, et al.
(author)
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Mechanochemical synthesis of (hetero)aryl Au(i) complexes
- 2020
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In: Green Chemistry. - : ROYAL SOC CHEMISTRY. - 1463-9262 .- 1463-9270. ; 22:17, s. 5648-5655
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Journal article (peer-reviewed)abstract
- Growing demand for sustainable chemical syntheses casts mechanochemistry in a new light as an environmentally benign alternative to traditional solvent-based methods. Given recent interest in Au(i) complexes for catalytic, materials, and medicinal applications, we developed a mechanochemical protocol to prepare (hetero)aryl Au(i) complexes under green conditions. The procedure reported here uses C-H or C-B activation to afford the corresponding Au(i) complexes in high yields. Our approach bypasses external heating, long reaction times and the use of toxic solvents. We demonstrate that mechanochemical C-H auration can be used on highly functionalised bioactive substrates. Mechanistic aspects of the C-H auration are discussed.
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| 4. |
- Ingner, Fredric, et al.
(author)
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Mild and Efficient Synthesis of Diverse Organo-Au-I-L Complexes in Green Solvents
- 2020
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In: ChemSusChem. - : WILEY-V C H VERLAG GMBH. - 1864-5631 .- 1864-564X. ; 13:8, s. 2032-2037
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Journal article (peer-reviewed)abstract
- An exceptionally mild and efficient method was developed for the preparation of (hetero)aryl-Au-I-L complexes using ethanol or water as the reaction medium at room temperature and Ar-B(triol)K boronates as the transmetalation partner. The reaction does not need an exogeneous base or other additives, and quantitative yields can be achieved through a simple filtration as the only required purification method, which obviates considerable waste associated with alternative workup methods. A broad reaction scope was demonstrated with respect to both the L and (hetero)aryl ligands on product Au complexes. Despite the polar reaction medium, large polycyclic aromatic hydrocarbon units can be incorporated on the Au complexes in very good to excellent yields. The approach was demonstrated for the chemoselective manipulation of orthogonally protected aryl boronates to afford a new class of N-heterocyclic carbene-Au-aryl complexes. A mechanistic rationale was proposed.
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| 5. |
- Ingner, Fredric
(author)
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New Strategies for Transition Metal-mediated (Hetero)arene Functionalization
- 2022
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Doctoral thesis (other academic/artistic)abstract
- This thesis describes new approaches to achieve efficient and selective (hetero)arene derivatization using transition metals. The main focus falls on the use of strategies based on C–H activation and organo-main group reactivity to render the synthesis of various (hetero)arene derivatives more direct, efficient, regioselective and sustainable. In the first two papers, transition metals are used to expedite the synthesis of aryne precursors and aryne capture products, as well as to influence the regioselectivity with which arynes may be made to react (Papers I and II). Paper I describes a new approach to the synthesis of aryne precursors from readily available arylboronic acids via a Ru-catalyzed C–H silylation protocol. The method tolerates a wide range of functional groups, affords access to new aryne motifs and only requires a single purification over multiple synthetic steps. Paper II explores how regioselectivity of aryne capture reactions can be enhanced significantly by remote cyclometallation using Ru, Rh and Ir. This work marks the first demonstration of exclusive regioselectivity in aryne capture reactions using only inductive electronic effects of a remotely substituted electropositive group.Papers III and IV concerns the synthesis of diverse aryl-AuI complexes under sustainable conditions. Paper III describes the use of a class of nucleophilic arylboronates, Ar-B(triol)K, to prepare aryl-AuI complexes in green solvents under ambient conditions without the requirement of exogenous additives or complex, expensive or time-consuming purification steps. This work is built upon in Paper IV where reaction solvents could be avoided altogether by employing a mechanochemical protocol and automated milling. The conditions developed allowed for C–H auration of various previously inaccessible (hetero)arenes and even the late-stage C–H auration of biologically active molecules. Both papers describe experiments performed to elucidate the intermediates and mechanism of C–H auration.
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| 6. |
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| 7. |
- Ingner, Fredric
(author)
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Sustainable methods for the preparation of diverse Au(I) complexes
- 2019
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Licentiate thesis (other academic/artistic)abstract
- Over the last three decades, the role of Au(I) complexes has become increasingly important within medicinal chemistry, material applications and synthesis. Alas, their preparation remains reliant on harsh reaction conditions, hazardous solvents, exogenous additives and, often, high reaction temperatures. Within this thesis we develop mild, sustainable, methods for the preparation of Au(I) complexes, that takes place in ambient conditions and omits the use of hazardous solvents. These goals are realized in two different manuscripts. The first manuscript utilizes a nucleophilic borate to afford Au(I) aryl complexes in green solvents without the requirement for exogenous additives. Purification consists of a simple filtration and washing step and affords products in very good to excellent yields for most examples. The second manuscript employs a mechanochemical protocol for expedient preparation of Au(I) aryl complexes from a number of parent aryl sources such as borates, arenes and heteroarenes. This includes the first mechanochemical preparation of Au(I) aryl complexes from borate or hetroarene sources. The developed mechanochemical C-H auration protocols allow for significantly less acidic C-H bonds than previously reported.
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| 8. |
- Kaul, Nidhi, 1992-, et al.
(author)
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Benzothiadiazole-Au(I) complexes as efficient room-temperature phosphors in solution
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Other publication (other academic/artistic)abstract
- A series of benzothiadiazole-Au(I) complexes with phosphine or carbene ligands has been synthesized, structurally characterized and investigated for their photophysical properties. These are the first organometallic Au(I) complexes that contains a C-Au bond on the highly electron-deficent benzothiadiazole unit. The complexes exhibit room temperature phosphorescence in solution (Fphos = 0.03-0.06), which is notable for mononuclear Au(I) complexes without intervening alkynyl bridges. [NK1] Their emissive nature was attributed to the triplet manifold of the benzothiadiazole motif that is efficently populated due to the direct linkage of gold. Hence, we show that direct C-auration of a weakly emissive aromatic heterocycle can gives access to efficent room temperature phosphorescence - a feature that is higly desirable for numerous applications within materials and life sciences.
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| 9. |
- Kunz, Susanna, et al.
(author)
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Derivatization of 2,1,3-Benzothiadiazole via Regioselective C–H Functionalization and Aryne Reactivity
- 2024
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In: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 89:9, s. 6138-6148
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Journal article (peer-reviewed)abstract
- Despite growing interest in 2,1,3-benzothiadiazole (BTD) as an integral component of many functional molecules, methods for the functionalization of its benzenoid ring have remained limited, and many even simply decorated BTDs have required de novo synthesis. We show that regioselective Ir-catalyzed C–H borylation allows access to versatile 5-boryl or 4,6-diboryl BTD building blocks, which undergo functionalization at the C4, C5, C6, and C7 positions. The optimization and regioselectivity of C–H borylation are discussed. A broad reaction scope is presented, encompassing ipso substitution at the C–B bond, the first examples of ortho-directed C–H functionalization of BTD, ring closing reactions to generate fused ring systems, as well as the generation and capture reactions of novel BTD-based heteroarynes. The regioselectivity of the latter is discussed with reference to the Aryne Distortion Model.
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| 10. |
- Ni, Shengjun, et al.
(author)
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Mechanochemical Solvent-Free Catalytic C-H Methylation
- 2021
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In: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 60:12, s. 6660-6666
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Journal article (peer-reviewed)abstract
- The mechanochemical, solvent-free, highly regioselective, rhodium-catalyzed C-H methylation of (hetero)arenes is reported. The reaction shows excellent functional-group compatibility and is demonstrated to work for the late-stage C-H methylation of biologically active compounds. The method requires no external heating and benefits from considerably shorter reaction times than previous solution-based C-H methylation protocols. Additionally, the mechanochemical approach is shown to enable the efficient synthesis of organometallic complexes that are difficult to generate conventionally.
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