Northwestern University.
J Am Chem Soc. 2011 Feb 16;133(6):1799-804. doi: 10.1021/ja109165f. Epub 2010 Dec 17.
The enantioselective total synthesis of the pyrrolophane natural product streptorubin B is described. Key steps in the concise route include the application of a one-pot enantioselective aldol cyclization/Wittig reaction and an anionic oxy-Cope rearrangement to forge the crucial 10-membered ring. Comparisons between CD spectra of synthetic and natural samples of streptorubin B coupled with X-ray crystallography allowed for the determination of the absolute stereochemistry of this natural product for the first time. These studies also provided unambiguous proof of the relative configuration between the butyl side chain and the bispyrrole subunit. Additional studies revealed a novel atropstereoselective Paal-Knorr pyrrole condensation and provided fundamental experimental insight into the barrier for atropisomerization of the natural product.
本文描述了吡咯并菲烷天然产物streptorubin B 的对映选择性全合成。简洁路线中的关键步骤包括应用一锅对映选择性羟醛环化/Wittig 反应和负离子氧-Cope 重排来构建关键的 10 元环。streptorubin B 的合成和天然样品的 CD 光谱比较以及 X 射线晶体学分析首次确定了该天然产物的绝对立体化学。这些研究还提供了丁基侧链和双吡咯亚基之间的相对构型的明确证据。进一步的研究揭示了一种新的对映选择性 Paal-Knorr 吡咯缩合反应，并为天然产物的对映体异构化势垒提供了基本的实验见解。
