Laboratorium für Organische Chemie, ETH Zürich, HCI H335, Wolfgang-Pauli-Strasse 10, 8093 Zürich (Switzerland) http://www.carreira.ethz.ch.
Angew Chem Int Ed Engl. 2013 Oct 11;52(42):11168-71. doi: 10.1002/anie.201305822. Epub 2013 Aug 26.
Fellowship of the ring: The first total synthesis of (+)-crotogoudin, a 3,4-seco-atisane diterpenoid natural product, is reported. Asymmetric access to the bicyclo[2.2.2]octane core is achieved through a desymmetrization of a meso-diketone with baker's yeast (LG=leaving group, PG=protecting group). A SmI2 -induced radical cyclopropane-opening/annulation/elimination cascade affords the suitably decorated tetracyclic structure of (+)-crotogoudin. The synthesis led to revision of the reported optical rotation of the natural product and to assignment of its absolute configuration as an ent-atisane (5R,10R).
首次全合成（+）-克罗托古丁，一种 3,4-裂环阿替烷二萜天然产物，被报道。通过贝克氏酵母（LG=离去基团，PG=保护基团）对中间二酮进行去对称化，实现了双环[2.2.2]辛烷核心的不对称进入。SmI2 诱导的自由基环丙烷开环/环加成/消除级联反应提供了（+）-克罗托古丁的适当修饰的四环结构。该合成导致对天然产物报道的旋光的修订，并确定其绝对构型为（5R,10R）-表阿替烷。
