Details
| Original language | English |
|---|---|
| Pages (from-to) | 5224-5235 |
| Number of pages | 12 |
| Journal | European Journal of Organic Chemistry |
| Issue number | 24 |
| Publication status | Published - 28 Nov 2005 |
Abstract
A multistep synthesis of the planar chiral tricarbonyl(η6- indan-1,2-dione)chromium, based on acetal protection of the keto groups, is presented. Since common deacetalization procedures failed, an oxidative deprotection with triphenylcarbenium tetrafluoroborate was used. Tricarbonyl(η6-indan-1,2-dione)chromium is regarded as a potential precursor for dianionic oxy-Cope rearrangements upon alkenyllithium diaddition. As an unexpected side product in the synthesis, an indan-1,2-dione complex with a triphenylmethyl substituent at C-3 was obtained. Attempts directed towards the formation of enantiomerically pure material include the first reported investigation into an enantioselective ketone reduction with two methoxy substituents present in the α position. Although enantiomeric excesses of up to 84.5% were achieved, the chemical yields decreased with increasing ee. A classical resolution was therefore undertaken, giving access to the enantiomerically pure title compound (99.4% ee). The absolute configuration was verified by an X-ray structure analysis of an intermediate. First experiments concerning the alkenyllithium addition showed that a single addition is possible while a second one does not occur, presumably due to enolate formation.
Keywords
- Arene ligands, Chromium complexes, Enantioselectivity, Indan-1,2-dione, Planar chirality
ASJC Scopus subject areas
- Chemistry(all)
- Physical and Theoretical Chemistry
- Chemistry(all)
- Organic Chemistry
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In: European Journal of Organic Chemistry, No. 24, 28.11.2005, p. 5224-5235.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Synthesis of enantiopure tricarbonyl(indan-1,2-dione)chromium
AU - Leinweber, Dirk
AU - Weidner, Ingo
AU - Wilhelm, René
AU - Wartchow, Rudolf
AU - Butenschön, Holger
PY - 2005/11/28
Y1 - 2005/11/28
N2 - A multistep synthesis of the planar chiral tricarbonyl(η6- indan-1,2-dione)chromium, based on acetal protection of the keto groups, is presented. Since common deacetalization procedures failed, an oxidative deprotection with triphenylcarbenium tetrafluoroborate was used. Tricarbonyl(η6-indan-1,2-dione)chromium is regarded as a potential precursor for dianionic oxy-Cope rearrangements upon alkenyllithium diaddition. As an unexpected side product in the synthesis, an indan-1,2-dione complex with a triphenylmethyl substituent at C-3 was obtained. Attempts directed towards the formation of enantiomerically pure material include the first reported investigation into an enantioselective ketone reduction with two methoxy substituents present in the α position. Although enantiomeric excesses of up to 84.5% were achieved, the chemical yields decreased with increasing ee. A classical resolution was therefore undertaken, giving access to the enantiomerically pure title compound (99.4% ee). The absolute configuration was verified by an X-ray structure analysis of an intermediate. First experiments concerning the alkenyllithium addition showed that a single addition is possible while a second one does not occur, presumably due to enolate formation.
AB - A multistep synthesis of the planar chiral tricarbonyl(η6- indan-1,2-dione)chromium, based on acetal protection of the keto groups, is presented. Since common deacetalization procedures failed, an oxidative deprotection with triphenylcarbenium tetrafluoroborate was used. Tricarbonyl(η6-indan-1,2-dione)chromium is regarded as a potential precursor for dianionic oxy-Cope rearrangements upon alkenyllithium diaddition. As an unexpected side product in the synthesis, an indan-1,2-dione complex with a triphenylmethyl substituent at C-3 was obtained. Attempts directed towards the formation of enantiomerically pure material include the first reported investigation into an enantioselective ketone reduction with two methoxy substituents present in the α position. Although enantiomeric excesses of up to 84.5% were achieved, the chemical yields decreased with increasing ee. A classical resolution was therefore undertaken, giving access to the enantiomerically pure title compound (99.4% ee). The absolute configuration was verified by an X-ray structure analysis of an intermediate. First experiments concerning the alkenyllithium addition showed that a single addition is possible while a second one does not occur, presumably due to enolate formation.
KW - Arene ligands
KW - Chromium complexes
KW - Enantioselectivity
KW - Indan-1,2-dione
KW - Planar chirality
UR - http://www.scopus.com/inward/record.url?scp=30044446152&partnerID=8YFLogxK
U2 - 10.1002/ejoc.200500527
DO - 10.1002/ejoc.200500527
M3 - Article
AN - SCOPUS:30044446152
SP - 5224
EP - 5235
JO - European Journal of Organic Chemistry
JF - European Journal of Organic Chemistry
SN - 1434-193X
IS - 24
ER -