Synthesis of the bis-spiroacetal moiety of the shellfish toxins spirolides B and D using an iterative oxidative radical cyclization strategy
作者:Kai Meilert、Margaret A. Brimble
DOI:10.1039/b604334h
日期:——
The enantioselective synthesis of the bis-spiroacetal fragment of the shellfish toxins, spirolides B 1 and D 2, is reported. The carbon framework was constructed via a Barbier reaction of dihydropyran 10 with aldehyde 11, followed by two oxidative radical cyclizations to construct the bis-spiroacetal ring system. A silyl-modified Prins cyclization and enantioselective crotylation successfully installed
据报道,贝类毒素的螺螺旋B 1和D 2的双螺缩醛片段的对映选择性合成。碳骨架是通过二氢吡喃10与醛11的Barbier反应构建的,然后进行两个氧化自由基环化以构建双螺缩醛环系统。甲硅烷基修饰的Prins环化和对映选择性的crotylation成功地在环化前体21中安装了立体中心。最初的不饱和双螺缩醛9a-d在环氧化成反式环氧化物24的过程中达到平衡,反式环氧化物24转化为叔醇7。