Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
Org Lett. 2011 Oct 21;13(20):5500-3. doi: 10.1021/ol2022214. Epub 2011 Sep 19.
Total syntheses of two structures purported as (+)-heliananes were completed in six pots. Spectral comparisons, between the synthetic and natural compounds, revealed a misassignment of the eight-membered ring in the heliananes. The key step in the syntheses of the proposed structures and the confirmation of their actual structures was a diastereoselective inverse-demand Diels-Alder reaction between an optically active enol ether and an ortho-quinone methide species, which was generated in situ at low temperature by the sequential addition of methylmagnesium bromide and di-tert-butyl dicarbonate to a salicylaldehyde.
据称（+）-海莲烷的两种结构的全合成在六个锅中完成。通过对合成化合物与天然化合物的光谱比较，发现海莲烷中环的八元环被错误指定。在所提出的结构的合成中的关键步骤以及对其实际结构的确认是通过在低温下通过顺次添加甲基溴化镁和二叔丁基二碳酸酯到水杨醛原位生成的手性活性烯醇醚和邻醌甲化物之间的非对映选择性反需求 Diels-Alder 反应。
