329-13-5Relevant academic research and scientific papers
Visible-light photoredox-catalyzed selective carboxylation of C(sp3)?F bonds with CO2
Bo, Zhi-Yu,Chen, Lin,Gao, Tian-Yu,Jing, Ke,Lan, Yu,Liu, Shi-Han,Luo, Shu-Ping,Yan, Si-Shun,Yu, Bo,Yu, Da-Gang
supporting information, p. 3099 - 3113 (2021/11/16)
It is highly attractive and challenging to utilize carbon dioxide (CO2), because of its inertness, as a nontoxic and sustainable C1 source in the synthesis of valuable compounds. Here, we report a novel selective carboxylation of C(sp3)?F bonds with CO2 via visible-light photoredox catalysis. A variety of mono-, di-, and trifluoroalkylarenes as well as α,α-difluorocarboxylic esters and amides undergo such reactions to give important aryl acetic acids and α-fluorocarboxylic acids, including several drugs and analogs, under mild conditions. Notably, mechanistic studies and DFT calculations demonstrate the dual role of CO2 as an electron carrier and electrophile during this transformation. The fluorinated substrates would undergo single-electron reduction by electron-rich CO2 radical anions, which are generated in situ from CO2 via sequential hydride-transfer reduction and hydrogen-atom-transfer processes. We anticipate our finding to be a starting point for more challenging CO2 utilization with inert substrates, including lignin and other biomass.
PROCESSES FOR FLUORINATION
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Paragraph 0179; 0184; 0214-0215; 0222, (2021/04/10)
The present technology relates to fluorination reactions. Specifically, processes useful for making the fungicide compound, DFT are disclosed. More broadly, also disclosed herein are processes useful for deoxyfluorination at the α-aromatic position of a given compound.
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.
Nucleophilic (Radio)Fluorination of Redox-Active Esters via Radical-Polar Crossover Enabled by Photoredox Catalysis
Webb, Eric W.,Park, John B.,Cole, Erin L.,Donnelly, David J.,Bonacorsi, Samuel J.,Ewing, William R.,Doyle, Abigail G.
supporting information, p. 9493 - 9500 (2020/05/18)
We report a redox-neutral method for nucleophilic fluorination of N-hydroxyphthalimide esters using an Ir photocatalyst under visible light irradiation. The method provides access to a broad range of aliphatic fluorides, including primary, secondary, and tertiary benzylic fluorides as well as unactivated tertiary fluorides, that are typically inaccessible by nucleophilic fluorination due to competing elimination. In addition, we show that the decarboxylative fluorination conditions are readily adapted to radiofluorination with [18F]KF. We propose that the reactions proceed by two electron transfers between the Ir catalyst and redox-active ester substrate to afford a carbocation intermediate that undergoes subsequent trapping by fluoride. Examples of trapping with O- and C-centered nucleophiles and deoxyfluorination via N-hydroxyphthalimidoyl oxalates are also presented, suggesting that this approach may offer a general blueprint for affecting redox-neutral SN1 substitutions under mild conditions.
Vessel Effect in C–F Bond Activation Prompts Revised Mechanism and Reveals an Autocatalytic Glycosylation
Nielsen, Michael M.,Qiao, Yan,Wang, Yingxiong,Pedersen, Christian M.
supporting information, p. 140 - 144 (2020/01/22)
Activation of C–F bonds under acidic conditions results in the formation of hydrogen fluoride as the reaction progresses. In the following communication, the effect of the vessel material on such reactions has been investigated and a significant differenc
PROCESSES FOR FLUORINATION
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Paragraph 0188, (2020/03/05)
The present technology relates to fluorination reactions. Specifically, processes useful for making the fungicide compound, DFT are disclosed. More broadly, also disclosed herein are processes useful for deoxyfluorination at the α-aromatic position of a given compound.
9-Borabicyclo[3.3.l]nonane-induced Friedel-Crafts benzylation of arenes with benzyl fluorides
Guo, Jing,Bamford, Karlee L.,Stephan, Douglas W.
supporting information, p. 5258 - 5261 (2019/06/07)
Friedel-Crafts benzylation of arenes with benzyl fluorides using 9-borabicyclo[3.3.l]nonane (9-BBN) as a mediator has been developed. This provides a simple and cheap route to the activation of C-F bonds to synthesize 1,1-diarylmethanes in good to excellent yields (up to 98%) under mild conditions. Functional group tolerance and the mechanism are considered.
Nucleophilic fluorination facilitated by a CsF-CaF2 packed bed reactor in continuous flow
Johansen,Lindhardt
supporting information, p. 825 - 828 (2018/02/06)
A simple to prepare, dry and handle packed bed reactor carrying CsF on CaF2, towards nucleophilic fluorinations in continuous flow, is reported. The reactor also proved adaptable for silyl-ether deprotection and trifluoromethylations with Ruppert's reagent. The study includes reactor stability and scale-up investigations.
Halogenation through Deoxygenation of Alcohols and Aldehydes
Chen, Jia,Lin, Jin-Hong,Xiao, Ji-Chang
supporting information, p. 3061 - 3064 (2018/05/28)
An efficient reagent system, Ph3P/XCH2CH2X (X = Cl, Br, or I), was very effective for the deoxygenative halogenation (including fluorination) of alcohols (including tertiary alcohols) and aldehydes. The easily available 1,2-dihaloethanes were used as key reagents and halogen sources. The use of (EtO)3P instead of Ph3P could also realize deoxy-halogenation, allowing for a convenient purification process, as the byproduct (EtO)3Pa?O could be removed by aqueous washing. The mild reaction conditions, wide substrate scope, and wide availability of 1,2-dihaloethanes make this protocol attractive for the synthesis of halogenated compounds.
Stereospecific Electrophilic Fluorination of Alkylcarbastannatrane Reagents
Ma, Xinghua,Diane, Mohamed,Ralph, Glenn,Chen, Christine,Biscoe, Mark R.
supporting information, p. 12663 - 12667 (2017/09/11)
We report the use of isolable primary and secondary alkylcarbastannatrane nucleophiles in site-specific fluorination reactions. These reactions occur without the need for transition metal catalysis or in situ activation of the nucleophile. In the absence of the carbastannatrane backbone, alkyltin nucleophiles exhibit no activity towards fluorination. When enantioenriched alkylcarbastannatranes are employed, fluorination occurs predominately via a stereoinvertive mechanism to generate highly enantioenriched alkyl fluoride compounds. These conditions can also be extended to stereospecific chlorination, bromination, and iodination reactions.
