| 1. |
- Demory, Emilien, et al.
(författare)
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Boryl (Hetero)aryne Precursors as Versatile Arylation Reagents : Synthesis through C-H Activation and Orthogonal Reactivity
- 2015
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 54:40, s. 11765-11769
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Tidskriftsartikel (refereegranskat)abstract
- (Pinacolato)boryl ortho-silyl(hetero)aryl triflates are presented as a new class of building blocks for arylation. They demonstrate unique versatility by delivering boronate or (hetero)aryne reactivity chemoselectively in a broad range of transformations. This approach enables the unprecedented postfunctionalization of fluoride-activated (hetero)aryne precursors, for example, as substrates in transition-metal catalysis, and offers valuable new possibilities for aryl boronate postfunctionalization without the use of specialized protecting groups.
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| 2. |
- Devaraj, Karthik, et al.
(författare)
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Arynes and Their Precursors from Arylboronic Acids via Catalytic C-H Silylation
- 2019
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Ingår i: Journal of Organic Chemistry. - : AMER CHEMICAL SOC. - 0022-3263 .- 1520-6904. ; 84:9, s. 5863-5871
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Tidskriftsartikel (refereegranskat)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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| 3. |
- Devaraj, Karthik, 1986-, et al.
(författare)
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Ru-Catalysed C-H Silylation of Gramines, Tryptamines and their Congeners
- 2016
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Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 52:34, s. 5868-5871
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Tidskriftsartikel (refereegranskat)abstract
- Selective Ru-catalysed C2–H silylation of heteroarenes is presented. The transformation works with or without directing group assistance and requires no protecting groups. Gramines and tryptamines may be converted efficiently whilst avoiding deleterious elimination side-reactions. Mechanistic studies reveal an unusual activation of the indole C4–H bond by an electron-rich metal.
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| 4. |
- Devaraj, Karthik
(författare)
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Ruthenium-catalyzed C-H Functionalization of (Hetero)arenes
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerned about the Ru-catalyzed C-H functionalizations on the synthesis of 2-arylindole unit, silylation of heteroarenes and preparation of aryne precursor.In the first project, we developed the Ru-catalyzed C2-H arylation of N-(2-pyrimidyl) indoles and pyrroles with nucleophilic arylboronic acids under oxidative conditions. Wide variety of arylboronic acids afforded the desired product in excellent yield regardless of the substituents or functional group electronic nature. Electron-rich heteroarenes are well suited for this method than electron-poor heteroarenes. Halides such as bromide and iodide also survived, further derivatisation of the halide is shown by Heck alkenylation. In order to find catalytic on-cycle intermediate extensive mechanistic experiments have been carried out by preparing presumed ruthenacyclic complexes and C-H/D exchange reactions. It suggested that para-cymene ligand is not present in the catalytic on-cycle intermediate and we suspect that metalation occurs with electrophilic ruthenium center via SEAr mechanism.In the second project, we developed the Ru-catalyzed silylation of gramine, tryptamine and their congeners using silanes as coupling partner. The transformation worked well with many different silanes. Regarding directing group, nitrogen atom containing directing groups are more favoured than the oxygen containing directing groups. Wide range of gramines and tryptamines also yielded the desired product in poor to excellent yield. At higher temperature, albeit in low yield, undirected silylation occurred. In order to get some insights about the reaction pathway of the silylation C-H/D exchange experiments were performed, and it revealed the possibility of C4-H activation of gramines by an electron rich metal- Si-H/D experiments showed Si-H activation by Ru is easy.In the final project, we presented the closely related aryne precursors from arylboronic acids via Ru-catalyzed C-H silylation of arylboronates and their selective oxidation. Worthy of note, the aryne capture products obtained from arylboronic acids in a single purification.
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| 5. |
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| 6. |
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| 7. |
- Larsson, Johanna, et al.
(författare)
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Selective Activation of Arylboronate or Aryne Reactivity as a Versatile Postfunctionalization Strategy
- 2016
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Ingår i: Synlett. - : Georg Thieme Verlag KG. - 0936-5214 .- 1437-2096. ; 27:7, s. 969-976
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Tidskriftsartikel (refereegranskat)abstract
- This review discusses the preparation and orthogonal reactivity of boryl ortho-silyl(hetero)aryl triflates as precursors for arynes. These triflates undergo a wide variety of selective reactions of either the boronate or aryne component. Activation of the boronate group affords diverse (hetero)aryne precursors, whereas aryne activation and capture gives previously difficult-to-access arylboronates, all starting from the same set of common starting materials. Thus, the boronate and aryne functionality can be used for their mutual postfunctionalization with unprecedented flexibility.
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| 8. |
- Sollert, Carina, et al.
(författare)
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Ru-Catalysed C-H Arylation of Indoles and Pyrroles with Boronic Acids : Scope and Mechanistic Studies
- 2015
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 21:14, s. 5380-5386
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Tidskriftsartikel (refereegranskat)abstract
- The Ru-catalysed C2-H arylation of indoles and pyrroles by using boronic acids under oxidative conditions is reported. This reaction can be applied to tryptophan derivatives and tolerates a wide range of functional groups on both coupling partners, including bromides and iodides, which can be further derivatised selectively. New indole based ruthenacyclic complexes are described and investigated as possible intermediates in the reaction. Mechanistic studies suggest the on-cycle intermediates do not possess a para-cymene ligand and that the on-cycle metalation occurs through an electrophilic attack by the Ru centre.
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| 9. |
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