Details
| Original language | English |
|---|---|
| Pages (from-to) | 680-691 |
| Number of pages | 12 |
| Journal | SYNLETT |
| Issue number | 6 |
| Publication status | Published - 1999 |
Abstract
As was first found on the basis of DSC measurements, bicyclo[3.2.0]heptadienyl cobalt complex 17 undergoes a ring opening - cycloaddition sequence at high temperature with formation of ring expansion products. Benzocyclobutene complexes react in a similar way only in one case. However, deprotonation of benzocyclobutenol complex endo-31 results in a dramatic decrease of the ring opening temperature and allows corresponding [4+2] cycloaddition reactions at low temperature. Benzocyclobutenedione complex 74 shows interesting structural features, its fragmentation in the mass spectrometer leads to η6 coordinated benzyne chromium cation. Addition of vinylmetal reagents induces a dianionic oxy-Cope rearrangement at -78°C, the first case of such a reaction at such mild reaction conditions. Products are benzannellated cyclooctenediones and their intramolecular aldol adducts, which are obtained with very high diastereoselectivity.
Keywords
- Benzocyclobutene complexes, Bicyclo[3.2.0]heptadienyl complexes, Chromium, Cobalt, Dianionic oxy-Cope rearrangement
ASJC Scopus subject areas
- Chemistry(all)
- Organic Chemistry
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In: SYNLETT, No. 6, 1999, p. 680-691.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - π Complexes with Annellated Cyclobutene Rings
T2 - Bicyclo[3.2.0]heptadienyl Anion and Benzocyclobutene as Ligands for Transition Metals
AU - Butenschön, Holger
PY - 1999
Y1 - 1999
N2 - As was first found on the basis of DSC measurements, bicyclo[3.2.0]heptadienyl cobalt complex 17 undergoes a ring opening - cycloaddition sequence at high temperature with formation of ring expansion products. Benzocyclobutene complexes react in a similar way only in one case. However, deprotonation of benzocyclobutenol complex endo-31 results in a dramatic decrease of the ring opening temperature and allows corresponding [4+2] cycloaddition reactions at low temperature. Benzocyclobutenedione complex 74 shows interesting structural features, its fragmentation in the mass spectrometer leads to η6 coordinated benzyne chromium cation. Addition of vinylmetal reagents induces a dianionic oxy-Cope rearrangement at -78°C, the first case of such a reaction at such mild reaction conditions. Products are benzannellated cyclooctenediones and their intramolecular aldol adducts, which are obtained with very high diastereoselectivity.
AB - As was first found on the basis of DSC measurements, bicyclo[3.2.0]heptadienyl cobalt complex 17 undergoes a ring opening - cycloaddition sequence at high temperature with formation of ring expansion products. Benzocyclobutene complexes react in a similar way only in one case. However, deprotonation of benzocyclobutenol complex endo-31 results in a dramatic decrease of the ring opening temperature and allows corresponding [4+2] cycloaddition reactions at low temperature. Benzocyclobutenedione complex 74 shows interesting structural features, its fragmentation in the mass spectrometer leads to η6 coordinated benzyne chromium cation. Addition of vinylmetal reagents induces a dianionic oxy-Cope rearrangement at -78°C, the first case of such a reaction at such mild reaction conditions. Products are benzannellated cyclooctenediones and their intramolecular aldol adducts, which are obtained with very high diastereoselectivity.
KW - Benzocyclobutene complexes
KW - Bicyclo[3.2.0]heptadienyl complexes
KW - Chromium
KW - Cobalt
KW - Dianionic oxy-Cope rearrangement
UR - http://www.scopus.com/inward/record.url?scp=0033038574&partnerID=8YFLogxK
U2 - 10.1055/s-1999-2700
DO - 10.1055/s-1999-2700
M3 - Article
AN - SCOPUS:0033038574
SP - 680
EP - 691
JO - SYNLETT
JF - SYNLETT
SN - 0936-5214
IS - 6
ER -