Details
| Original language | English |
|---|---|
| Pages (from-to) | 322-327 |
| Number of pages | 6 |
| Journal | Journal of the Chemical Society of Pakistan |
| Volume | 26 |
| Issue number | 3 |
| Publication status | Published - Dec 2004 |
Abstract
Reactions of metal complexes of π systems with anellated rings are presented. These include thermal ring expansions of the bicyclo[3.2.0]hepta-1,3- dienylcobalt(I) system as well as a benzocyclobutene tricarbonylchromium complex. More important are, however, a number of oxy-anion driven reactions, which take place at temperatures as low as -78 °C. These include the ring opening of the hydroxybenzocyclobutene complex followed by a [4+2] cycloaddition with dienophiles and an anion driven ring expansion of the benzoyclobutenone complex upon acyl anion addition. The benzocyclobutenedione tricarbonylhromium complex allows a nucleophilic diaddition from the face opposite to the tricarbonylchromium group. If this is done with alkenyllithium reagents a dianionic oxy-Cope rearrangement takes place at - 78 °C, which is followed by a selective intramolecular aldol addition. Some asymmetric cases of this chemistry are reported, in which two different enolate moieties in one eight-membered ring are perfectly discriminated. It is further reported that the dianionic oxy-Cope rearrangement also takes place upon vinyllithium addition to acyclic 1,2-diones. A short synthesis of benzocyclobutenedion from ninhydrin is presented. Finally the syntheses of the tricarbonylchomium complexes of 1,3-indandione and of 1,2,3-indantrione are reported.
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Journal of the Chemical Society of Pakistan, Vol. 26, No. 3, 12.2004, p. 322-327.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Cyclic π systems with anellated rings
T2 - Highly selective oxy-anion driven Reactions at chromium complexes
AU - Butenschön, Holger
PY - 2004/12
Y1 - 2004/12
N2 - Reactions of metal complexes of π systems with anellated rings are presented. These include thermal ring expansions of the bicyclo[3.2.0]hepta-1,3- dienylcobalt(I) system as well as a benzocyclobutene tricarbonylchromium complex. More important are, however, a number of oxy-anion driven reactions, which take place at temperatures as low as -78 °C. These include the ring opening of the hydroxybenzocyclobutene complex followed by a [4+2] cycloaddition with dienophiles and an anion driven ring expansion of the benzoyclobutenone complex upon acyl anion addition. The benzocyclobutenedione tricarbonylhromium complex allows a nucleophilic diaddition from the face opposite to the tricarbonylchromium group. If this is done with alkenyllithium reagents a dianionic oxy-Cope rearrangement takes place at - 78 °C, which is followed by a selective intramolecular aldol addition. Some asymmetric cases of this chemistry are reported, in which two different enolate moieties in one eight-membered ring are perfectly discriminated. It is further reported that the dianionic oxy-Cope rearrangement also takes place upon vinyllithium addition to acyclic 1,2-diones. A short synthesis of benzocyclobutenedion from ninhydrin is presented. Finally the syntheses of the tricarbonylchomium complexes of 1,3-indandione and of 1,2,3-indantrione are reported.
AB - Reactions of metal complexes of π systems with anellated rings are presented. These include thermal ring expansions of the bicyclo[3.2.0]hepta-1,3- dienylcobalt(I) system as well as a benzocyclobutene tricarbonylchromium complex. More important are, however, a number of oxy-anion driven reactions, which take place at temperatures as low as -78 °C. These include the ring opening of the hydroxybenzocyclobutene complex followed by a [4+2] cycloaddition with dienophiles and an anion driven ring expansion of the benzoyclobutenone complex upon acyl anion addition. The benzocyclobutenedione tricarbonylhromium complex allows a nucleophilic diaddition from the face opposite to the tricarbonylchromium group. If this is done with alkenyllithium reagents a dianionic oxy-Cope rearrangement takes place at - 78 °C, which is followed by a selective intramolecular aldol addition. Some asymmetric cases of this chemistry are reported, in which two different enolate moieties in one eight-membered ring are perfectly discriminated. It is further reported that the dianionic oxy-Cope rearrangement also takes place upon vinyllithium addition to acyclic 1,2-diones. A short synthesis of benzocyclobutenedion from ninhydrin is presented. Finally the syntheses of the tricarbonylchomium complexes of 1,3-indandione and of 1,2,3-indantrione are reported.
UR - http://www.scopus.com/inward/record.url?scp=30044437946&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:30044437946
VL - 26
SP - 322
EP - 327
JO - Journal of the Chemical Society of Pakistan
JF - Journal of the Chemical Society of Pakistan
SN - 0253-5106
IS - 3
ER -