Gibberellin analogues by reaction of 7-oxo-diterpenes with diacetoxyiodobenzene
In this work, the reaction of 7-oxo-diterpenes with diacetoxyiodobenzene (DIB) has been proved to be a good method for the preparation of gibberellin analogues, which can be applied to diterpenes with endocyclic or exocyclic double bonds. It has been studied with ent-kaur-16-ene, ent-trachylobane and ent-atis-16-ene diterpenes. Thus, the reaction of 7-oxo-ent-kaur-16-en-18-oic acid methyl ester and 7-oxo-ent-trachyloban-16-en-18-oic acid methyl ester with this reagent affords 4-epi-gibberellin A12 dimethyl ester and 4-epi-trachylobagibberellin A12 dimethyl ester, respectively. In some cases, especially with compounds functionalized at C-19, alternative reactions lead to the introduction in the substrate of a conjugated 5,6-double bond or to the formation of a ketal at the 6-position. Thus, the formation of gibberellin analogues, dehydrogenation products or 6-ketal derivatives depend on the neighbouring group participation of the C-18 (equatorial) and C-19 (axial) substituents at C-4.
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Elsevier
2013-04-08
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| Subjects: | 4-epi-Trachylobagibberellin A12, ent-Kaur-16-ene, Diterpenes, ent-Trachylobane, ent-Atis-16-ene, Diacetoxyiodobenzene, |
| Online Access: | http://hdl.handle.net/10261/178561 http://dx.doi.org/10.13039/501100006280 http://dx.doi.org/10.13039/501100000780 http://dx.doi.org/10.13039/501100003339 |
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| Summary: | In this work, the reaction of 7-oxo-diterpenes with diacetoxyiodobenzene (DIB) has been proved to be a good method for the preparation of gibberellin analogues, which can be applied to diterpenes with endocyclic or exocyclic double bonds. It has been studied with ent-kaur-16-ene, ent-trachylobane and ent-atis-16-ene diterpenes. Thus, the reaction of 7-oxo-ent-kaur-16-en-18-oic acid methyl ester and 7-oxo-ent-trachyloban-16-en-18-oic acid methyl ester with this reagent affords 4-epi-gibberellin A12 dimethyl ester and 4-epi-trachylobagibberellin A12 dimethyl ester, respectively. In some cases, especially with compounds functionalized at C-19, alternative reactions lead to the introduction in the substrate of a conjugated 5,6-double bond or to the formation of a ketal at the 6-position. Thus, the formation of gibberellin analogues, dehydrogenation products or 6-ketal derivatives depend on the neighbouring group participation of the C-18 (equatorial) and C-19 (axial) substituents at C-4. |
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