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Intramolecular Diels-Alder reactions. 5 - Facile synthesis of an octahydrobenzocycloheptenone derivative utilising intramolecular Diels-Alder reaction
被引:0
|作者:
Frey, B
[1
]
Reissig, HU
[1
]
机构:
[1] Tech Univ Dresden, Inst Organ Chem, D-01062 Dresden, Germany
来源:
JOURNAL FUR PRAKTISCHE CHEMIE-CHEMIKER-ZEITUNG
|
1999年
/
341卷
/
02期
关键词:
carbocycles;
cycloadditions;
Lewis acids;
titanium;
cycloheptanone;
D O I:
10.1002/(SICI)1521-3897(199902)341:2<173::AID-PRAC173>3.0.CO;2-M
中图分类号:
O69 [应用化学];
学科分类号:
081704 ;
摘要:
Undecatrienone 4 was prepared in a short sequence via siloxycyclopropanes 1 and 3. Intramolecular Diels-Alder reaction (IMDA) of 4 under various conditions afforded octahydrobenzocycloheptenone derivative 5 as a mixture of three or four diastereomers. High diastereoselectivities in favour of the endo-product cis-5a could be obtained with TiCl4 as promoter. This selectivities were attributed to the formation of a seven-membered ring chelate as intermediate. The configurational assignment of all four diastereomers of 5 was based on isomerisation reactions and NMR analysis.
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页码:173 / 178
页数:6
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