Gymnomitranes

For the stereoselective total synthesis of bazzanene (12 Scheme 8), a sesquiterpene isolated from the liverwort Bazzania pompeana, the fragmentation of the monoprotected mesylate (10) was used. The mesylate (10) is obtained from the triol (9), an intermediate in the synthesis of gymnomitrane sesquiter-penes. Treatment of (10) with KOBu produces cleanly the expected cyclohexenone (11). 

Total syntheses of gymnomitrane-type sesquiterpenes confirm the structure of these biogenetically interesting compounds. ( )-Gymnomitrol (123) and a- and p-barbatene (121, 122) have been synthesized by five different laboratories as shown in Schemes 18 — 23 (98,107,134,176, 285, 344,345). 

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