Synthetic studies towards complex diterpenoids. Part 13. Stereo-specific synthesis of intermediates to the diterpene alkaloids and the C20-gibberellins by a novel rearrangement of angularly fused cyclo-butanones
specific labelled ketone [2H2]-(10a) indicate that the process is intramolecular. Sulphuric acid-catalysed rearrangement of (10a) produces the unsaturated methyl ketone (13). Transformation of the tetracyclic ketones (5a and b) to some angularly functionalised hydrofluorene synthons (14a and b) to the C20-gibberellins has been achieved.
描述了使用四氟硼酸三乙基氧鎓将饱和的环丁酮(10a和b)和(11a和b)分别立体连接成各自的桥联环戊酮(2a和b)和(5a和b)。特定标记的酮[ 2 H 2 ]-(10a)的重排研究表明该过程是分子内的。硫酸催化的(10a)重排产生不饱和甲基酮(13)。已经实现了将四环酮(5a和b)转化为一些具有角度功能的氢芴合成子(14a和b)转化为C 20-赤霉素。