Diterpenic skeleton transformations : alumina catalysed rearrangements of epoxides

✍ Scribed by Martine Taran; Bernard Delmond

• Publisher: Elsevier Science
• Year: 1982
• Tongue: French
• Weight: 189 KB
• Volume: 23
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)85887-6

✦ Synopsis

The 8,14 8-epoxide of methyl sandaracopimarate undergoes new rearrangements on contact with active alumina, yielding labdane and another compound having the cycloisopimarane skeleton. In an earlier paper' dealing with the reactivity of methyl sandaracopimarate 8,14 8 epoxide l_ towards boron trifluoride etherate, the hydroxy-olefinz was obtained by a backbone rearrangement. The results obtained by Sukh Dev* and 0urisson3showing that the action of active alumina is different from that of BF3:Et20 when working with monoterpene and sesquiterpene derivatives promptedus to investigate the behaviour of epoxideA towards this reagent. Thus treatment of l_in yielded a mixture of carbonyl and basis of spectral data. cyclohexane solution, during 12 h with active neutral alumina hydroxy compounds whose structures were established on the // The carbonyl fraction included the ketones $, (2 %), recently described', and2 (11 %) and the aldehydez (5 X).