Details
| Original language | English |
|---|---|
| Pages (from-to) | 1192-1200 |
| Number of pages | 9 |
| Journal | Chemistry - a European journal |
| Volume | 4 |
| Issue number | 7 |
| Publication status | Published - 10 Jul 1998 |
Abstract
A versatile approach towards the highly strained acepentalene 3 via the readily accessible dipotassium acepentalenediide (10a) and the highly strained tetraenes 7 is reported. An unexpected [4+2] cycloaddition dimer 14 is formed upon protonation of the dipotassium acepentalenediide (10a) in 93% yield, and the monomeric 4,7-dihydroacepentalene (7a), as the reactive intermediate, can be trapped with anthracene to form the corresponding Diels-Alder adduct 16 in 15% yield. In contrast, the highly strained, but sterically protected monomeric bridgehead-bridgehead alkenes 7c,d can be isolated upon reaction of 10a or 10b with bulky electrophiles, such as Me3-SiCl and Me3SnCl, respectively. The X-ray crystal structure analysis of 7d exhibits a highly pyramidalized central double bond. The bisstannane 7d is an ideal precursor for acepentalene (3), which would be formed by removal of the two trimethylstannyl substituents. It can also be transmetallated to give the pure crystalline dilithium acepentalenediide (10b) in 78% yield. According to its 1H, 7Li and 13C NMR spectra, the bowl-shaped 12π-dianion in 10b is an aromatic species, and it undergoes a rapid bowl-to-bowl inversion at room temperature.
Keywords
- Acepentalene, Alkenes, Aromaticity, Polyquinanes, Strained molecules
ASJC Scopus subject areas
- Chemical Engineering(all)
- Catalysis
- Chemistry(all)
- Organic Chemistry
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In: Chemistry - a European journal, Vol. 4, No. 7, 10.07.1998, p. 1192-1200.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Syntheses, Structures, and Reactions of Highly Strained Dihydro- and Tetrahydroacepentalene Derivatives
AU - Haag, Rainer
AU - Schüngel, Franz Manfred
AU - Ohlhorst, Björk
AU - Lendvai, Thomas
AU - Butenschön, Holger
AU - Clark, Timothy
AU - Noltemeyer, Mathias
AU - Haumann, Thomas
AU - Boese, Roland
AU - De Meijere, Armin
PY - 1998/7/10
Y1 - 1998/7/10
N2 - A versatile approach towards the highly strained acepentalene 3 via the readily accessible dipotassium acepentalenediide (10a) and the highly strained tetraenes 7 is reported. An unexpected [4+2] cycloaddition dimer 14 is formed upon protonation of the dipotassium acepentalenediide (10a) in 93% yield, and the monomeric 4,7-dihydroacepentalene (7a), as the reactive intermediate, can be trapped with anthracene to form the corresponding Diels-Alder adduct 16 in 15% yield. In contrast, the highly strained, but sterically protected monomeric bridgehead-bridgehead alkenes 7c,d can be isolated upon reaction of 10a or 10b with bulky electrophiles, such as Me3-SiCl and Me3SnCl, respectively. The X-ray crystal structure analysis of 7d exhibits a highly pyramidalized central double bond. The bisstannane 7d is an ideal precursor for acepentalene (3), which would be formed by removal of the two trimethylstannyl substituents. It can also be transmetallated to give the pure crystalline dilithium acepentalenediide (10b) in 78% yield. According to its 1H, 7Li and 13C NMR spectra, the bowl-shaped 12π-dianion in 10b is an aromatic species, and it undergoes a rapid bowl-to-bowl inversion at room temperature.
AB - A versatile approach towards the highly strained acepentalene 3 via the readily accessible dipotassium acepentalenediide (10a) and the highly strained tetraenes 7 is reported. An unexpected [4+2] cycloaddition dimer 14 is formed upon protonation of the dipotassium acepentalenediide (10a) in 93% yield, and the monomeric 4,7-dihydroacepentalene (7a), as the reactive intermediate, can be trapped with anthracene to form the corresponding Diels-Alder adduct 16 in 15% yield. In contrast, the highly strained, but sterically protected monomeric bridgehead-bridgehead alkenes 7c,d can be isolated upon reaction of 10a or 10b with bulky electrophiles, such as Me3-SiCl and Me3SnCl, respectively. The X-ray crystal structure analysis of 7d exhibits a highly pyramidalized central double bond. The bisstannane 7d is an ideal precursor for acepentalene (3), which would be formed by removal of the two trimethylstannyl substituents. It can also be transmetallated to give the pure crystalline dilithium acepentalenediide (10b) in 78% yield. According to its 1H, 7Li and 13C NMR spectra, the bowl-shaped 12π-dianion in 10b is an aromatic species, and it undergoes a rapid bowl-to-bowl inversion at room temperature.
KW - Acepentalene
KW - Alkenes
KW - Aromaticity
KW - Polyquinanes
KW - Strained molecules
UR - http://www.scopus.com/inward/record.url?scp=0031822595&partnerID=8YFLogxK
U2 - 10.1002/(SICI)1521-3765(19980710)4:7<1192::AID-CHEM1192>3.0.CO;2-G
DO - 10.1002/(SICI)1521-3765(19980710)4:7<1192::AID-CHEM1192>3.0.CO;2-G
M3 - Article
AN - SCOPUS:0031822595
VL - 4
SP - 1192
EP - 1200
JO - Chemistry - a European journal
JF - Chemistry - a European journal
SN - 0947-6539
IS - 7
ER -