Convergent Approach to Pumiliotoxin Alkaloids. Asymmetric Total Synthesis of (+)-Pumiliotoxins A, B, and 225F
作者:Sakae Aoyagi、Shintaro Hirashima、Kosuke Saito、Chihiro Kibayashi
DOI:10.1021/jo0200466
日期:2002.8.1
(Z)-iodoalkylidene indolizidine 34, which served as a common key intermediate, was synthesized through highly stereoselective addition of the chiral silylallene 19 to (S)-acetylpyrrolidine followed by a palladium-catalyzed intramolecular carbonylation[bond]cyclization sequence. This synthetic process allowed the first total synthesis of (+)-pumiliotoxin 225F. The intermediate (Z)-iodoalkylidene indolizidine 34 obtained
利用Pd(0)催化的均烯酸有机锌和乙烯基碘化物之间的交叉偶联反应,已经开发了一种通用的会聚方法来制备pumiliotoxin生物碱。通过将手性甲硅烷基亚烷基19高度立体选择性地加成到(S)-乙酰基吡咯烷中,然后钯催化的分子内羰基化键合环化序列,合成了用作常见关键中间体的(Z)-碘亚烷基吲哚并吡啶34。该合成过程允许(+)-pumiliotoxin 225F的第一个全合成。将获得的中间体(Z)-碘亚烷基吲哚并吡啶34转化为均烯丙基氯化锌衍生物,并使用Pd(PPh(3))(4)催化剂与(E)-乙烯基碘42进行均烯丙基-乙烯基交叉偶联,得到带有1,5-二烯侧链的交叉偶联产物47。