作者:Lisa J. Alcock、Matthew D. Norris、Michael V. Perkins
DOI:10.1039/c7ob03150e
日期:——
Two putative structures of spongosoritin A, with syn (6R,8R) and anti (6S,8R) configurations, were each synthesised in a total of 11 linear steps with only 8 purification procedures. The key steps in our strategy included Evans alkylation and olefin dihydroxylation to install the C8 and C6 stereocentres, a transacetalisation/dehydration cascade to construct the furanylidene core, and chromatographic
合成的海绵丝蛋白A的两个推定结构,分别具有syn(6 R,8 R)和抗(6 S,8 R)构型,每一个步骤仅用8个纯化步骤即可合成总共11个线性步骤。我们策略中的关键步骤包括Evans烷基化和烯烃二羟基化以安装C8和C6立体中心,反缩醛化/脱水级联反应以构建呋喃二烯核,以及将最终化合物的9 E-和9 Z-异构体与硝酸银进行色谱分离浸渍的二氧化硅。合成syn的1 H和13 C NMR数据比较-和天然产物报道的抗异构体表明,海绵素A的相对构型是syn。基于旋光度的测量,也证实了绝对立体化学为6 R,8 R,其中合成syn(6 R,8 R)和天然产物具有相同的旋光度(负)。