Chemistry of (+)-aromadendrene. Part 6: Rearrangement reactions of ledene, isoledene and their epoxides

✍ Scribed by F.Javier Moreno-Dorado; Yvonne M.A.W Lamers; Grigore Mironov; Joannes B.P.A Wijnberg; Aede de Groot

• Publisher: Elsevier Science
• Year: 2003
• Tongue: French
• Weight: 237 KB
• Volume: 59
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(03)01231-6

✦ Synopsis

The chemistry of (þ)-ledene and (2)-isoledene, both easily available from (þ)-aromadendrene has been investigated. Reactions at the double bond of ledene take place preferably from the b-side. Under acidic conditions its C7 -C8 b-epoxide and b-diol preferably react via carbocations, which are initially formed at C8. Rearrangement takes place to compounds with cubebane and cadinane skeletons. The reaction pattern of isoledene and its a-epoxide, under acidic conditions, is governed by the easy formation of an intermediate a-cyclopropylcarbinyl carbocation. Further reactions lead to products in which the C2-C3 bond of the cyclopropane ring is broken to give compounds with a guaiane skeleton. Guaiane-type dienes and unsaturated cyclic ethers are the final products of these rearrangements. Several derivatives of these compounds have been prepared.