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  • From cyclic (alkyl)(amino)carbene (CAAC) precursors to fluorinating reagents [Elektronski vir] : experimental and theoretical study
    Gruden, Evelin ...
    Addition of anhydrous HF to the hydrochloride [MeCAACH][Cl(HCl)0.5] resulted in the formation of salts with high HF content. By stepwise removal of HF in vacuo, we selectively prepared ... [MeCAACH][F(HF)2] (3) and [MeCAACH][F(HF)3] (4). We also characterised a salt with [F(HF)4]− anions within the structure of [MeCAACH][F(HF)3.5] (5). Compounds with a lower content of HF were not accessible under vacuum conditions. MeCAAC(H)F (1) was selectively prepared by abstraction of HF from 3 with CsF or KF, while [MeCAACH][F(HF)] (2) was prepared by mixing 3 and 1 in a 1 : 1 ratio. Compound 2 proved to be quite unstable as it tends to disproportionate into 1 and 3. This observation triggered our computational study, in which the structural relationships between CAAC-based fluoropyrrolidines and dihydropyrrolium fluorides were investigated using different DFT methods. The study showed that the results were very sensitive to the computational method used. For a correct description, the quality of the triple-ζ basis set was crucial. Surprisingly, the isodesmic reaction of [MeCAACH][F] + [MeCAACH][F(HF)2] → [MeCAACH][F(HF)] + [MeCAACH][F(HF)] did not confirm the low thermodynamic stability of 2. Furthermore, the use of 3 as a nucleophilic fluorinating reagent was tested on a range of organic substrates, as it is the most stable compound in this series. It was found to have the potential to fluorinate benzyl bromides, 1- and 2-alkyl bromides, silanes and sulfonyls with good to excellent yields of the target fluorides.
    Vir: Dalton transactions [Elektronski vir]. - ISSN 1477-9234 (Vol. 52, iss. 28, Jul. 2023, str. 9562-9572)
    Vrsta gradiva - e-članek ; neleposlovje za odrasle
    Leto - 2023
    Jezik - angleški
    COBISS.SI-ID - 160299011

    Povezava(-e):

    https://pubs.rsc.org/en/content/articlelanding/2023/DT/D3DT01476B
    Repozitorij Univerze v Ljubljani – RUL
    DOI

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