Diterpenoids of mixed biogenesis in phaeophyta biogenetic-type interconversions
In the course of research into marine natural products, the diterpenoids taondiol 10 and atomaric acid 15, were isolated from the brown seaweed Taonia atomaria.The similarities of these structures plus the fact that both compounds come from the same alga suggest that there ny be a biogenetic relationship between the two. This speculated relationship is adumbratted in Sxcheme 1, where the cyclic and acyclic diterpenoids of mixed biogenesis isolated from Phaeophyta are interrelated. In the present work, the competitive cyclisation of the proposed olefinic intermediate 4 to the naturally occurring compounds taondiol 10, isotandiol 11, epitaondiol 12 and stypodiol 13, is repoeted. The stereoselective ytansformation of atomaric acid 15 into the compound 4 is also reprted, which transformation pccurs by intramolecular carbocyclisation of the olefinic aldehyde 7 followed by backbone rearrangement to the olefine 4. This result prompted the proposal that atomaric acid 15 may arise in nature by means of a like rearrangement but operating in a reverse direction.
| Main Authors: | , , , , , |
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| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Elsevier
1982
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| Online Access: | http://hdl.handle.net/10261/23843 |
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| Summary: | In the course of research into marine natural products, the diterpenoids taondiol 10 and atomaric acid 15, were isolated from the brown seaweed Taonia atomaria.The similarities of these structures plus the fact that both compounds come from the same alga suggest that there ny be a biogenetic relationship between the two. This speculated relationship is adumbratted in Sxcheme 1, where the cyclic and acyclic diterpenoids of mixed biogenesis isolated from Phaeophyta are interrelated. In the present work, the competitive cyclisation of the proposed olefinic intermediate 4 to the naturally occurring compounds taondiol 10, isotandiol 11, epitaondiol 12 and stypodiol 13, is repoeted. The stereoselective ytansformation of atomaric acid 15 into the compound 4 is also reprted, which transformation pccurs by intramolecular carbocyclisation of the olefinic aldehyde 7 followed by backbone rearrangement to the olefine 4. This result prompted the proposal that atomaric acid 15 may arise in nature by means of a like rearrangement but operating in a reverse direction. |
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