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Borylation of fluorinated arenes using the boron centred nucleophile B(CN)\(_{3}\)\(^{2-}\) - a unique entry to aryltricyanoborates
Please always quote using this URN: urn:nbn:de:bvb:20-opus-170417
- The potassium salt of the boron-centred nucleophile B(CN)\(_{3}\)\(^{2-}\)(1) readily reacts with perfluorinated arenes, such as hexafluorobenzene, decafluorobiphenyl, octafluoronaphthalene and pentafluoropyridine, which results in KF and the K\(^{+}\) salts of the respective borate anions with one {B(CN)\(_{3}\)} unit bonded to the (hetero)arene. An excess of K\(_{2}\)1 leads to the successive reaction of two or, in the case of perfluoropyridine, even three C–F moieties and the formation of di- and trianions, respectively. Moreover, all of theThe potassium salt of the boron-centred nucleophile B(CN)\(_{3}\)\(^{2-}\)(1) readily reacts with perfluorinated arenes, such as hexafluorobenzene, decafluorobiphenyl, octafluoronaphthalene and pentafluoropyridine, which results in KF and the K\(^{+}\) salts of the respective borate anions with one {B(CN)\(_{3}\)} unit bonded to the (hetero)arene. An excess of K\(_{2}\)1 leads to the successive reaction of two or, in the case of perfluoropyridine, even three C–F moieties and the formation of di- and trianions, respectively. Moreover, all of the 11 partially fluorinated benzene derivatives, C\(_{6}\)F\(_{6-n}\)H\(_{n}\) (n = 1–5), generally react with K\(_{2}\)1 to give new tricyano(phenyl)borate anions with high chemo- and regioselectivity. A decreasing number of fluorine substituents on benzene results in a decrease in the reaction rate. In the cases of partially fluorinated benzenes, the addition of LiCl is advantageous or even necessary to facilitate the reaction. Also, pentafluorobenzenes R–C\(_{6}\)F\(_{5}\) (R = –CN, –OMe, –Me, or –CF\(_{3}\)) react via C–F/C–B exchange that mostly occurs in the para position and to a lesser extent in the meta or ortho positions. Most of the reactions proceed via an S\(_{N}\)Ar mechanism. The reaction of 1,4-F\(_{2}\)C\(_{6}\)H\(_{4}\) with K\(_{2}\)1 shows that an aryne mechanism has to be considered in some cases as well. In summary, a wealth of new stable tricyano(aryl)borates have been synthesised and fully characterized using multi-NMR spectroscopy and most of them were characterised using single-crystal X-ray diffraction.…
Author: | Johannes Landmann, Philipp T. Hennig, Nikolai V. Ignat'ev, Maik FinzeORCiD |
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URN: | urn:nbn:de:bvb:20-opus-170417 |
Document Type: | Journal article |
Faculties: | Fakultät für Chemie und Pharmazie / Institut für Anorganische Chemie |
Language: | English |
Parent Title (English): | Chemical Science |
Year of Completion: | 2017 |
Volume: | 8 |
Issue: | 9 |
Pagenumber: | 5962-5968 |
Source: | Chemical Science, 2017, 8(9), 5962-5968. DOI: 10.1039/c7sc02249b |
DOI: | https://doi.org/10.1039/c7sc02249b |
Pubmed Id: | https://pubmed.ncbi.nlm.nih.gov/28989626 |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 546 Anorganische Chemie |
Tag: | aryltricyanoborates; boron-centred nucleophile; borylation |
Release Date: | 2019/09/25 |
Licence (German): | CC BY: Creative-Commons-Lizenz: Namensnennung |