Gibberellin analogues by reaction of 7-oxo-diterpenes with diacetoxyiodobenzene
作者:Braulio M. Fraga、Victoria González-Vallejo、Carlo Bressa、Ricardo Guillermo、Sergio Suárez
DOI:10.1016/j.tet.2013.01.092
日期:2013.4
(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
在这项工作中,已证明7-氧代二萜与二乙酰氧基碘苯(DIB)的反应是制备赤霉素类似物的好方法,可用于具有环内或环外双键的二萜。已经用ent -kaur-16-ene,ent -trachylobane和ent -atis-16-ene二萜对它进行了研究。因此,该反应-7-氧代- ENT -kaur -16-烯-18- OIC酸甲酯和7-氧代ENT -trachyloban -16-烯-18- OIC酸甲酯与该试剂,得到4-外延-赤霉素A 12二甲酸酯和4- epi- trachylobagbagberberin A 12二甲酯。在某些情况下,尤其是在C-19官能化的化合物的情况下,替代反应导致在底物中引入共轭的5,6-双键或在6位上形成缩酮。因此,赤霉素类似物,脱氢产物或6-缩酮衍生物的形成取决于在C-4处C-18(赤道)和C-19(轴向)取代基的相邻基团参与。
Neighbouring group participation in the reaction of 7-oxo-ent-kaur-16-ene derivatives with diacetoxyiodobenzene. Synthesis of gibberellin analogues
作者:Braulio M. Fraga、Carlo Bressa、Victoria González-Vallejo、Sergio Suárez、Ricardo Guillermo
DOI:10.1016/j.tetlet.2011.10.111
日期:2011.12
The reaction of different 7-oxo-ent-kaur-16-ene derivatives with diacetoxyiodobenzene has been evaluated for the preparation of gibberellin analogues. Thus, the reaction of 7-oxo-ent-kaur-16-en-18-oic acid methyl ester (3) with this reagent afforded 4-epi-GA12 dimethyl ester (6). This reaction constitutes a good procedure for the preparation of this type of compounds. In some cases, alternative reactions