[reaction: see text] A model C1-C14 segment (1) of halichondrin B was synthesized from (+)-conduritol E (7) in 18 steps and 2.9% overall yield. Key features of the synthesis include the novel ozonolytic desymmetrization of C(2)-symmetric diol 6, the early-stage construction of the C-ring which accompanies installation of the crucial C12 stereocenter, and the use of an enol ether C14-ketone surrogate
[反应:参见正文]由(+)-松节
油醇E(7)以18个步骤合成halichondrin B的模型C1-C14片段(1),总产率为2.9%。合成的关键特征包括C(2)-对称二醇6的新型
臭氧分解脱对称,关键C12立体中心的安装过程中C环的早期构建以及烯醇醚C14-酮替代物的使用作为CDE“笼养”
缩酮的前身。