- Bicyclooctenones in Synthesis. A New Synthesis of (+/-)-Cedrene using Sequential Inter- and Intra-molecular Michael Reactions
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A new synthetic approach to cedrene (1) based on sequential inter- and intra-molecular Michael reactions using the bicyclooctenone (21) as the key intermediate is described.Michael addition of the enolate derived from (21) to 2-nitrobut-2-ene, led to a mixture of diastereoisomers of the nitro ketone (22), which was then converted into the 1,4-dione (23).Treatment of (23) with potassium t-butoxide in t-butyl alcohol resulted in smooth intramolecular Michael reaction leading to a mixture of α- (24a; major) and β-isomers of the tricyclo1,5>undecanedione (24) in a combined yield of 73percent.The undecanedione (24) was then converted into (+/-)-cedrene (1) and the corresponding methyl epimer (31a) via the intermediates (25), (26), (27), and (28).
- Horton, Michael,Pattenden, Gerald
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p. 811 - 817
(2007/10/02)
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- A NEW SYNTHESIS OF (+/-)-CEDRENE USING SEQUENTIAL INTER- AND INTRA-MOLECULAR MICHAEL REACTIONS
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A synthesis of (+/-)-cedrene (1), which features sequential intermolecular i.e.(2) -> (7), and intramolecular i.e. (8) -> (9), Michael reactions using the bicyclooctenone (2) as key intermediate, is described.
- Horton, Michael,Pattenden, Gerald
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p. 2125 - 2128
(2007/10/02)
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