SYNTHESIS OF METHYL-SUBSTITUTED BICYCLO[3.2.0]HEPT-3-EN-6-ONES AND 3,3A,4,6A-TETRAHYDRO-2H-CYCLOPENTA[B]FURAN-2-ONES

Treatment of methyl mono- or bisubstituted 3-hydroxy-6-alkenoic acids in acetic anhydride and potassium acetate give the corresponding bicyclo[3.2.0]hept-3-en-6-ones in fair to good yields. This reaction appears to be of general applicability to prepare the methyl derivatives in all the positions of...

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Bibliographic Details
Published inTetrahedron Vol. 50; no. 25; pp. 7645 - 7656
Main Authors MAROTTA, E, PAGANI, RIGHI, P, ROSINI, G
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier 1994
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
(+/-)-HIRSUTENE
DIENES
KETENES
LACTONES
INITIATED POLYOLEFINIC CYCLIZATIONS
RADICAL CYCLIZATION
ESTERS
(R)-(-)-CARVONE
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Summary:Treatment of methyl mono- or bisubstituted 3-hydroxy-6-alkenoic acids in acetic anhydride and potassium acetate give the corresponding bicyclo[3.2.0]hept-3-en-6-ones in fair to good yields. This reaction appears to be of general applicability to prepare the methyl derivatives in all the positions of the five membered ring. The synthesis of 4,7,7-trimethylbicyclo[3.2.0]hept-3-en-6-one (filifolone) by an efficient bicyclization of 3-hydroxy-3-methyl-6-heptenoic acid followed by the geminal dimethylation of the intermediate 4-methylbicyclo[3.2.0]hept-3-en-6-one is reported. The latter reaction proved to be a general method when performed on bicyclo[3.2.0]hept-3-en-6-ones and on bicyclo[3.2.0]hept-2-en-6-one. 3,3a,4,6a-Tetrahydro-2H-cyclopenta[b]furan-2-ones, important starting materials in the synthesis of linear condensed triquinane sesquiterpenes, have been prepared in an efficient manner by the easy bicyclization of 3-hydroxy-6-heptenoic acids, followed by a Baeyer-Villiger oxidation of the bicyclo[3.2.0]hept-3-en-6-one intermediates.
ISSN:0040-4020
DOI:10.1016/S0040-4020(01)90491-0