Model Studies Directed toward the Alkaloid Mersicarpine Utilizing a Rh(II)-Catalyzed Insertion/Cycloaddition Sequence
作者:Hao Li、Sara A. Bonderoff、Bo Cheng、Albert Padwa
DOI:10.1021/jo4026622
日期:2014.1.3
stereocenters and three continuous quaternary carbons in a single operation in high yield with excellent diastereoselectivity. The 3-indolinone derivative 36 was eventually formed from cycloadduct 22 by an acid-induced hydrolysis of 22 to give 23, which was subsequently converted in several steps to 36. The synthesis of this compound constitutes a successful construction of the tricyclic core of mersicarpine
作为几种生物碱类美卡西平的方法,已经进行了有关铑(II)催化的类胡萝卜素插入/环化/环加成级联反应的几种α-重氮二氢吲哚满酮的模型研究。α-重氮二氢吲哚满酮21的级联反应以高收率和极好的非对映选择性进行,从而得到环加合物22,该环加合物具有在美西卡平中存在的两个相邻的季碳中心所需的立体化学。整个反应使多环体系能够快速组装,该体系包含三个新的立体中心和三个连续的季碳原子,一次即可高收率,具有非对映选择性。3-吲哚酮衍生物36最终由环加合物形成22通过的酸诱导的水解22,得到23,将其随后转化在几个步骤36。该化合物的合成构成了美卡西平的三环核心的成功构建。如相关化合物29所发现的,还原36的腈基团,随后进行随后的还原环化/开环芳构化级联反应,将用于最终合成脱甲基美沙芬。