Our first-generation synthetic study towards the total synthesis of propindilactone G (1) and its analogues is reported. The key synthetic steps were an intramolecular Pauson-Khand reaction (PKR) and a vinylogous Mukaiyama reaction (VMAR). The stereoselective synthesis of the CDE ring moiety with an all-carbon quaternary center through a PKR was difficult, whilst a VMAR afforded a product with the opposite stereochemistry at the C20 position on the side chain. These results led us to redesign our synthetic strategy for the total synthesis of compound 1.
A concise total synthesis of (+)‐propindilactone G, a nortriterpenoid isolated from the stems of Schisandra propinqua var. propinqua, has been achieved for the first time. The key steps include an asymmetric Diels–Alder reaction, a Pauson–Khand reaction, a Pd‐catalyzed reductive hydrogenolysis reaction, and an oxidative heterocoupling reaction. These reactions enabled the synthesis in only 20 steps. As a consequence of our synthetic studies, the structure of propindilactone G has been revised. More information can be found in their Full Papers on pages 1406, 1414, and 1425 by Zhen Yang and Jia‐Hua Chen et al. in Issue 9, 2016 (DOI: 10.1002/asia.201600129, 10.1002/asia.201600130, 10.1002/asia.201600131.).
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