29263-69-2Relevant academic research and scientific papers
Thiourea-Catalyzed C?F Bond Activation: Amination of Benzylic Fluorides
Houle, Camille,Savoie, Paul R.,Davies, Clotilde,Jardel, Damien,Champagne, Pier Alexandre,Bibal, Brigitte,Paquin, Jean-Fran?ois
, p. 10620 - 10625 (2020/07/24)
We describe the first thiourea-catalyzed C?F bond activation. The use of a thiourea catalyst and Ti(OiPr)4 as a fluoride scavenger allows the amination of benzylic fluorides to proceed in moderate to excellent yields. Preliminary results with S- and O-based nucleophiles are also presented. DFT calculations reveal the importance of hydrogen bonds between the catalyst and the fluorine atom of the substrate to lower the activation energy during the transition state.
Metal-Free C-O Bond Functionalization: Catalytic Intramolecular and Intermolecular Benzylation of Arenes
Bering, Luis,Jeyakumar, Kirujan,Antonchick, Andrey P.
supporting information, p. 3911 - 3914 (2018/07/22)
A catalytic, metal-free intramolecular rearrangement of benzyl phenyl ethers using nitrosonium salt as a catalyst is described. The optimized reaction conditions enabled a catalytic and metal-free Friedel-Crafts alkylation reaction with benzylic alcohols, producing water as the stoichiometric byproduct. A comprehensive scope (>50 examples) for both approaches and application in drug synthesis were demonstrated. Mechanistic studies suggest a Lewis acid-based mechanism for the metal-free Friedel-Crafts reaction.
Deep Eutectic Solvent Compatible Metallic Catalysts: Cationic Pyridiniophosphine Ligands in Palladium Catalyzed Cross-Coupling Reactions
Marset, Xavier,Khoshnood, Abbas,Sotorríos, Lia,Gómez-Bengoa, Enrique,Alonso, Diego A.,Ramón, Diego J.
, p. 1269 - 1275 (2017/04/14)
Cationic pyridiniophosphine ligands have been synthetized in an attempt to develop a deep eutectic solvents (DESs) compatible catalytic systems. These ligands, in combination with PdCl2, have been successfully applied to different palladium-catalyzed cross coupling reactions, such as Suzuki–Miyaura, Sonogashira, or Heck couplings. While traditional palladium ligands in DES medium failed to reproduce the results obtained in VOC solvents, these cationic phosphines improved the catalytic activity of palladium as no other traditional ligand could in such a polar medium. In addition, the recyclability of these processes was studied, allowing us to reuse both, catalyst and solvent up to 5 times in Suzuki and Sonogashira reactions without a significant drop in the catalytic activity. Regarding the structure of the Pd catalysts, titration, NMR, and DFT studies have clearly demonstrated the coordination properties of the DES-compatible cationic phosphine ligands.
From insertion to multicomponent coupling: Temperature dependent reactions of arynes with aliphatic alcohols
Thangaraj, Manikandan,Bhojgude, Sachin Suresh,Mane, Manoj V.,Biju, Akkattu T.
supporting information, p. 1665 - 1668 (2016/01/30)
The temperature dependent selectivity switch in the reaction of arynes with aliphatic alcohols in THF has been reported. At -20°C, arynes smoothly insert into the O-H bond of alcohols to form alkyl aryl ethers. Interestingly, at 60°C, a highly selective multicomponent coupling occurs with the solvent THF acting as the nucleophilic trigger affording (4-(alkoxy)butoxy)arenes.
Enabling nucleophilic substitution reactions of activated alkyl fluorides through hydrogen bonding
Champagne, Pier Alexandre,Pomarole, Julien,Therien, Marie-Eve,Benhassine, Yasmine,Beaulieu, Samuel,Legault, Claude Y.,Paquin, Jean-Francois
, p. 2210 - 2213 (2013/06/26)
It was discovered that the presence of water as a cosolvent enables the reaction of activated alkyl fluorides for bimolecular nucleophilic substitution reactions. DFT calculations show that activation proceeds through stabilization of the transition structure by a stronger F···H 2O interaction and diminishing C-F bond elongation, and not simple transition state electrostatic stabilization. Overall, the findings put forward a distinct strategy for C-F bond activation through H-bonding.
Palladium-catalyzed substitution and cross-coupling of benzylic fluorides
Blessley, George,Holden, Patrick,Walker, Matthew,Brown, John M.,Gouverneur, Veronique
, p. 2754 - 2757 (2012/07/16)
Benzylic fluorides are suitable substrates for Pd(0)-catalyzed Tsuji-Trost substitution using carbon, nitrogen, oxygen, and sulfur nucleophiles and for cross-coupling with phenylboronic acid. For the bifunctional substrate 4-chlorobenzyl fluoride, fine-tuning of the reaction conditions allows for the regioselective displacement of either the chlorine or fluorine substituent. The leaving group ability of fluoride vs other groups displaced in substitution is CF3CO2 ≈ p-NO2C6H 4CO2 ≈ OCO2CH3 > F > CH3CO2, a ranking similar to allylic fluorides under Pd catalysis.
Fragmentation of anion radicals with elimination of aryloxy groups
Dneprovskii,Fedosov
, p. 1438 - 1443 (2007/10/03)
4-Vinylbenzyl phenyl ether, 4-phenylbenzyl phenyl ether, 1- and 2-naphthylmethyl phenyl ethers react with sodium thiophenolate under photochemical stimulation with replacement of the phenoxy group. The composition of reaction products and relation of reactivity to the structure of substrates is consistent with anion-radical mechanism. The corresponding methoxy and cyano derivatives do not undergo the reaction.
