Department of Chemistry, University of Chicago, Chicago, IL, 60637, USA.
Angew Chem Int Ed Engl. 2020 May 11;59(20):7848-7856. doi: 10.1002/anie.201915821. Epub 2020 Mar 12.
To show the synthetic utility of the catalytic C-C activation of less strained substrates, described here are the collective and concise syntheses of the natural products (-)-microthecaline A, (-)-leubehanol, (+)-pseudopteroxazole, (+)-seco-pseudopteroxazole, pseudopterosin A-F and G-J aglycones, and (+)-heritonin. The key step in these syntheses involve a Rh-catalyzed C-C/C-H activation cascade of 3-arylcyclopentanones, which provides a rapid and enantioselective route to access the polysubstituted tetrahydronaphthalene cores presented in these natural products. Other important features include 1) the direct C-H amination of the tetralone substrate in the synthesis of (-)-microthecaline A, 2) the use of phosphoric acid to enhance efficiency and regioselectivity for problematic cyclopentanone substrates in the C-C activation reactions, and 3) the direct conversion of serrulatane into amphilectane diterpenes by an allylic cyclodehydrogenation coupling.
为了展示催化 C-C 激活较少张力底物的综合实用性，这里集中而简洁地合成了天然产物 (-)-microthecaline A、(-)-leubehanol、(+) - pseudopteroxazole、(+) - seco-pseudopteroxazole、pseudopterosin A-F 和 G-J 苷元和 (+)-heritonin。这些合成中的关键步骤涉及 Rh 催化的 3-芳基环戊酮的 C-C/C-H 激活级联反应，该反应提供了一种快速和对映选择性的方法来获得这些天然产物中存在的多取代四氢萘核。其他重要特征包括 1）在 (-)-microthecaline A 的合成中直接对四氢萘酮底物进行 C-H 氨化，2）在 C-C 激活反应中使用磷酸以提高效率和区域选择性来处理有问题的环戊酮底物，以及 3）通过烯丙基环脱氢偶联直接将旋覆花烷转化为 Amphilectane 二萜。
