Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 3132-3141 |
| Seitenumfang | 10 |
| Fachzeitschrift | European Journal of Organic Chemistry |
| Ausgabenummer | 16 |
| Publikationsstatus | Veröffentlicht - 20 Apr. 2012 |
Abstract
The generation of (η6-aryne)chromium complexes as reactive intermediates was investigated in two ways. Although earlier attempts directed towards triflate eliminations from a variety of tricarbonyl(phenyl triflate)chromium complexes had failed, more electron-rich phenyl triflate complexes were considered. This was accomplished either by substitution with two methoxy groups in the arene ligand or by replacement of one of the three carbonyl ligands of the tricarbonylchromium complex with triphenylphosphane. However, the attempted elimination still did not take place; in spite of the increased electron densities in the aromatic ligands, anionic thia-Fries rearrangements were observed in high yields at -78 °C. As an alternative, elimination of lithium fluoride was tested. Tricarbonyl(2-lithiofluorobenzene) chromium(0) was generated by tin/lithium exchange. After hydrolytic workup, tricarbonyl(fluorobenzene)chromium was obtained as the main product, indicating that the lithiation step had been successful. A dimeric side product provided evidence for the intermediacy of (benzyne)tricarbonylchromium.
ASJC Scopus Sachgebiete
- Chemie (insg.)
- Physikalische und Theoretische Chemie
- Chemie (insg.)
- Organische Chemie
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in: European Journal of Organic Chemistry, Nr. 16, 20.04.2012, S. 3132-3141.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Attempts directed towards the synthesis of intermediate (aryne)chromium complexes from aryl triflates and from (haloarene)chromium complexes
AU - Werner, Georg
AU - Butenschön, Holger
PY - 2012/4/20
Y1 - 2012/4/20
N2 - The generation of (η6-aryne)chromium complexes as reactive intermediates was investigated in two ways. Although earlier attempts directed towards triflate eliminations from a variety of tricarbonyl(phenyl triflate)chromium complexes had failed, more electron-rich phenyl triflate complexes were considered. This was accomplished either by substitution with two methoxy groups in the arene ligand or by replacement of one of the three carbonyl ligands of the tricarbonylchromium complex with triphenylphosphane. However, the attempted elimination still did not take place; in spite of the increased electron densities in the aromatic ligands, anionic thia-Fries rearrangements were observed in high yields at -78 °C. As an alternative, elimination of lithium fluoride was tested. Tricarbonyl(2-lithiofluorobenzene) chromium(0) was generated by tin/lithium exchange. After hydrolytic workup, tricarbonyl(fluorobenzene)chromium was obtained as the main product, indicating that the lithiation step had been successful. A dimeric side product provided evidence for the intermediacy of (benzyne)tricarbonylchromium.
AB - The generation of (η6-aryne)chromium complexes as reactive intermediates was investigated in two ways. Although earlier attempts directed towards triflate eliminations from a variety of tricarbonyl(phenyl triflate)chromium complexes had failed, more electron-rich phenyl triflate complexes were considered. This was accomplished either by substitution with two methoxy groups in the arene ligand or by replacement of one of the three carbonyl ligands of the tricarbonylchromium complex with triphenylphosphane. However, the attempted elimination still did not take place; in spite of the increased electron densities in the aromatic ligands, anionic thia-Fries rearrangements were observed in high yields at -78 °C. As an alternative, elimination of lithium fluoride was tested. Tricarbonyl(2-lithiofluorobenzene) chromium(0) was generated by tin/lithium exchange. After hydrolytic workup, tricarbonyl(fluorobenzene)chromium was obtained as the main product, indicating that the lithiation step had been successful. A dimeric side product provided evidence for the intermediacy of (benzyne)tricarbonylchromium.
KW - Anionic thia-Fries rearrangement
KW - Arynes
KW - Chromium
KW - Haloarenes
KW - Lithiation
KW - Phenyl triflate
KW - Rearrangement
UR - http://www.scopus.com/inward/record.url?scp=84862062749&partnerID=8YFLogxK
U2 - 10.1002/ejoc.201200176
DO - 10.1002/ejoc.201200176
M3 - Article
AN - SCOPUS:84862062749
SP - 3132
EP - 3141
JO - European Journal of Organic Chemistry
JF - European Journal of Organic Chemistry
SN - 1434-193X
IS - 16
ER -