Stereoselective synthesis of new 8-oxabicyclo[3.2.1]oct-6-en-2-one and 8-oxabicyclo[3.2.1]octa-3,6-dien-2-one derivatives. The electron-releasing and electron-withdrawing effects of homoconjugated ketones

Two successive brominations of 8-oxabicyclo[3.2.1]oct-6-en-2-one 6 provided 3-exo,6-exo,7-endo-tribromo-7oxabicyclo[3.2.1]octan-2-endo-one 10 with high stereoselectivity. NaBH4 reduced 10 into 3-exo, 6-exo,7-endo-tribromo-8-oxabicyclo[3.2.1]octan-2-endo-ol exclusively. Selective elimination of one equivalent of HBr from 10 furnished 3-exo,7-dibromo-8-oxabicyclo[3.2.1]oct-6-en-2-endo-ol 13. Regio- and stereoselective addition of PhSeCl to enone 6, followed by alpha -ketone bromination and treatment with a base led selectively to 7-(phenylseleno)-8-oxabicyclo[3.2.1]octa-3,6-dien-2-one 20. The high selectivities observed are attributed to steric factors and to electronic factors such as electron-releasing or electron-withdrawing effects of homoconjugated carbonyl group.


Published in:
Indian Journal of Chemistry Section B-Organic Chemistry Including Medicinal Chemistry, 40, 10, 898-904
Year:
2001
ISSN:
0376-4699
Keywords:
Note:
Univ Lausanne, BCH, Sect Chem, CH-1015 Lausanne, Switzerland.
Laboratories:




 Record created 2005-11-09, last modified 2018-03-17


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