Total Synthesis of the Cytotoxic <i>Threo</i>, <i>Trans</i>, <i>Threo</i>, <i>Trans</i>, <i>Threo</i> Annonaceous Acetogenin Asimin and Its C-10 Epimer: Unambiguous Confirmation of Absolute Stereochemistry
作者:James A. Marshall、Hongjian Jiang
DOI:10.1021/np990132+
日期:1999.8.1
essential features of this synthesis include (a) the addition of an enantioenriched gamma-OMOM allylic indium reagent to a core C-23 aldehyde precursor to install the C-24-C-34 segment with concomitant introduction of the C-24 and C-23 stereocenters; (b) the addition of an enantioenriched gamma-OMOM allylic indium reagent to a core C-16 aldehyde to install the C-10-C-15 segment with formation of the
报道了asimin(1)及其C-10差向异构体33的收敛合成。该合成的基本特征包括:(a)向核心C-23醛前体中添加对映体富集的γ-OMOM烯丙基铟试剂,以安装C-24-C-34链段,同时引入C-24和C -23个立体中心;(b)向核心C-16醛中添加对映体富集的γ-OMOM烯丙基铟试剂以安装C-10-C-15片段并形成C-15和C-16立体中心,(c)添加手性三溴化物-Ti(Oi-Pr)(4)配合物催化的二烷基锌试剂引入C-1-C-9片段,并生成10(R)或10(S)立体中心;(d)前述的C-1-C-34链段与OTBS保护的乳醛的醛醇缩合,以掺入C-35-C-37丁烯内酯链段。用THF中的HCl水溶液除去三个MOM保护基。发现10(R)非对映异构体对应于天然asimin。