369-00-6Relevant academic research and scientific papers
Deoxyfluorination of Carboxylic Acids with CpFluor: Access to Acyl Fluorides and Amides
Wang, Xiu,Wang, Fei,Huang, Fengfeng,Ni, Chuanfa,Hu, Jinbo
supporting information, p. 1764 - 1768 (2021/03/03)
3,3-Difluoro-1,2-diphenylcyclopropene (CpFluor), a bench-stable fluorination reagent, has been developed in the deoxyfluorination of carboxylic acids to afford various acyl fluorides. This all-carbon-based fluorination reagent enabled the efficient transformation of (hetero)aryl, alkyl, alkenyl, and alkynyl carboxylic acids to the corresponding acyl fluorides under the neutral conditions. This deoxyfluorination method was featured by the synthesis of acyl fluorides with in-situ formed CpFluor, as well as the one-pot amidation reaction of carboxylic acids via in-situ formed acyl fluorides.
Acyl fluorides from carboxylic acids, aldehydes, or alcohols under oxidative fluorination
Liang, Yumeng,Zhao, Zhengyu,Taya, Akihito,Shibata, Norio
supporting information, p. 847 - 852 (2021/02/06)
We describe a novel reagent system to obtain acyl fluorides directly from three different functional group precursors: carboxylic acids, aldehydes, or alcohols. The transformation is achieved via a combination of trichloroisocyanuric acid and cesium fluoride, which facilitates the synthesis of various acyl fluorides in high yield (up to 99%). It can be applied to the late-stage functionalization of natural products and drug molecules that contain a carboxylic acid, an aldehyde, or an alcohol group.
Cooperative NHC/Photoredox Catalyzed Ring-Opening of Aryl Cyclopropanes to 1-Aroyloxylated-3-Acylated Alkanes
Daniliuc, Constantin G.,Studer, Armido,Zuo, Zhijun
supporting information, p. 25252 - 25257 (2021/10/29)
Cyclopropanes are an important class of building blocks in organic synthesis. Herein, a ring-opening/arylcarboxylation/acylation cascade reaction for the 1,3-difunctionalization of aryl cyclopropanes enabled by cooperative NHC and organophotoredox catalysis is reported. The cascade works on monosubstituted cyclopropanes that are in contrast to the heavily investigated donor–acceptor cyclopropanes more challenging to be difunctionalized. The key step is a radical/radical cross coupling of a benzylic radical generated in the photoredox catalysis cycle with a ketyl radical from the NHC catalysis cycle. The transformation features metal-free reaction conditions and tolerates a diverse range of functionalities.
Cooperative NHC and Photoredox Catalysis for the Synthesis of β-Trifluoromethylated Alkyl Aryl Ketones
D?ben, Nadine,Meng, Qing-Yuan,Studer, Armido
supporting information, p. 19956 - 19960 (2020/09/04)
Despite the great potential of radical chemistry in organic synthesis, N-heterocyclic carbene (NHC)-catalyzed reactions involving radical intermediates are not well explored. This communication reports the three-component coupling of aroyl fluorides, styrenes and the Langlois reagent (CF3SO2Na) to give various β-trifluoromethylated alkyl aryl ketones with good functional group tolerance in moderate to high yields by cooperative photoredox/NHC catalysis. The alkene acyltrifluoromethylation proceeds via radical/radical cross coupling of ketyl radicals with benzylic C-radicals. The ketyl radicals are generated via SET reduction of in situ formed acylazolium ions whereas the benzylic radicals derive from trifluoromethyl radical addition onto styrenes.
Benzoyl Fluorides as Fluorination Reagents: Reconstruction of Acyl Fluorides via Reversible Acyl C-F Bond Cleavage/Formation in Palladium Catalysis
Ogiwara, Yohei,Hosaka, Shintaro,Sakai, Norio
, p. 856 - 861 (2020/03/05)
This report describes the formation of value-added acyl fluorides by means of palladium-catalyzed acyl-exchange reactions between acyl fluorides and acid anhydrides. This method allows using a simple and commercially available acyl fluoride, benzoyl fluoride, as the fluoride source for the easy and efficient preparation of a variety of more complex acyl fluorides. The results of this study suggest that this reaction proceeds via a reversible acyl C-F bond cleavage/formation at the palladium center.
Synthesis of acyl fluorides via photocatalytic fluorination of aldehydic C-H bonds
Meanwell, Michael,Lehmann, Johannes,Eichenberger, Marc,Martin, Rainer E.,Britton, Robert
supporting information, p. 9985 - 9988 (2018/09/11)
Acyl fluorides are versatile acylating agents owing to their unique stability. Their synthesis, however, can present challenges and is typically accomplished through deoxyfluorination of carboxylic acids. Here, we demonstrate that acyl fluorides can be prepared directly from aldehydes via a C(sp2)-H fluorination reaction involving the inexpensive photocatalyst sodium decatungstate and electrophilic fluorinating agent N-fluorobenzenesulfonimide. This convenient fluorination strategy enables direct conversion of aliphatic and aromatic aldehydes into acylating agents.
Enantioselective acylation of silyl ketene acetals through fluoride anion-binding catalysis
Birrell, James A.,Desrosiers, Jean-Nicolas,Jacobsen, Eric N.
supporting information; experimental part, p. 13872 - 13875 (2011/10/09)
A highly enantioselective acylation of silyl ketene acetals with acyl fluorides has been developed to generate useful α,α-disubstituted butyrolactone products. This transformation is promoted by a new thiourea catalyst and 4-pyrrolidinopyridine and represents the first example of enantioselective thiourea anion-binding catalysis with fluoride.
The Relationship between 19F Substituent Chemical Shifts and Electron Densities: meta- and para-Substituted Benzoyl Fluorides
Brownlee, Robert T. C.,Craik, David J.
, p. 186 - 191 (2007/10/02)
The 19F substituent chemical shifts (SCS) of meta- and para-benzoyl fluorides are found to correlate well with substituent parameters using the dual substituent parameter (DSP) equation, indicating that they reflect electronic perturbations induced by the substituent.The direction of the SCS values is such that donating substituents cause upfield shifts whilst acceptors cause downfield shifts.STO-3G calculations indicate that substituents induce only very small changes in ?-electron density about the fluorine atom, but that these changes correlate reasonably well with the observed SCS values.For the para series, the slope of the relationship between Δq?F and 19F SCS is 5000 ppm/electron, indicating the great sensitivity of the fluorine atom to small changes in electron density.
