CFH groups are unique due to the combination of their lipophilic and hydrogen bonding properties. The strength of H-bonding is determined by the group to which it is appended. Several functional groups have been explored in this context including O, S, SO and SO to tune the intermolecular interaction. Difluoromethyl ketones are under-studied in this context, without a broadly accessible method for their preparation. Herein, we describe the development of an electrochemical hydrodefluorination of readily accessible trifluoromethylketones. The single-step reaction at deeply reductive potentials is uniquely amenable to challenging electron-rich substrates and reductively sensitive functionality. Key to this success is the use of non-protic conditions enabled by an ammonium salt that serves as a reductively stable, masked proton source. Analysis of their H-bonding has revealed difluoromethyl ketones to be potentially highly useful dual H-bond donor/acceptor moieties.
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http://dx.doi.org/10.1039/d1sc01574e | DOI Listing |
J Org Chem
November 2024
Institute of Material Physics & Chemistry, College of Science, Nanjing Forestry University, Nanjing 210037, P. R. China.
A comprehensive and effective electrochemical methodology is introduced for the diverse hydrodechlorination of -dichlorocyclopropanes and the ring cleavage hydrodefluorination of -difluorocyclopropanes under uniform electrochemical conditions. Moreover, the water content allows for the adjustable monohydrodechlorination or dihydrodechlorination of -dichlorocyclopropanes with exceptional chemoselectivity. Additionally, the mildness and practicality of this protocol facilitate its application to the late-stage functionalization of bioactive molecules.
View Article and Find Full Text PDFOrg Lett
March 2024
School of Chemistry, Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, Xi'an Key Laboratory of Sustainable Energy Material Chemistry, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China.
We report a simple and economical method to synthesize monofluoroalkenes via the electrochemical hydrodefluorination of -difluoroalkenes. This reaction proceeds efficiently at room temperature, eliminating the requirement for a costly transition metal catalyst, ligand, and external reducing agent. The monofluoroalkene products can be obtained in medium to good yields and up to 99:1 / selectivity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2023
School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
We report a general procedure for the direct mono- and di-hydrodefluorination of ArCF compounds. Exploiting the tunability of electrochemistry and the selectivity enabled by a Ni cathode, the deep reduction garners high selectivity with good to excellent yields up to gram scale. The late-stage peripheral editing of CF feedstocks to construct fluoromethyl moieties will aid the rapid diversification of lead-compounds and compound libraries.
View Article and Find Full Text PDFChemistry
May 2022
Department of Chemistry, College of Jiyang, Zhejiang A&F University, Zhuji, Zhejiang, 311800, P. R. China.
Hydrodefluorination (HDF) is a very important fundamental transformation for conversion of the C-F bond into the C-H bond in organic synthesis. In the past decade, much progress has been achieved with HDF through the utility of low-valent metals, transition-metal complexes and main-group Lewis acids. Recently, novel methods have been introduced for this purpose through photo- and electrochemical pathways, which are of great significance, due to their considerable environmental and economical advantages.
View Article and Find Full Text PDFChem Sci
January 2022
Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg Albertstr. 21 79104 Freiburg Germany
Already 1 mol% of subvalent [Ga(PhF)][] ([] = [Al(OR)], R = C(CF)) initiates the hydrosilylation of olefinic double bonds under mild conditions. Reactions with HSiMe and HSiEt as substrates efficiently yield -Markovnikov and -addition products, while bulkier substrates such as HSiPr are less reactive. Investigating the underlying mechanism by gas chromatography and STEM analysis, we unexpectedly found that H and metallic Ga formed.
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