Stereoselective Total Synthesis of Hetisine‐type C20‐Diterpenoid Alkaloids: Spirasine IV and XI |
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| Authors: | Quanzheng Zhang Zhongshan Zhang Zhong Huang Changhui Zhang Song Xi Prof?Dr Min Zhang |
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| Affiliation: | Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Innovative Drug Research Centre, School of Pharmaceutical Sciences, Chongqing University, Shapingba, Chongqing, China |
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| Abstract: | The first total synthesis of the architecturally complex hetisine‐type heptacyclic C20‐diterpenoid alkaloids (±)‐spirasine IV and XI is reported. The A/F/G/C tetracyclic skeleton with the challenging N?C6 and C14?C20 linkages was efficiently constructed by an intramolecular azomethine‐ylide‐based 1,3‐dipolar cycloaddition with unusual regioselectivity. SmI2‐mediated free‐radical addition to the arene moiety without prior dearomatization and a stereoselective intramolecular aldol reaction further enabled rapid access to the hetisine core, providing a bicyclo2.2.2]octane ring with a new oxygen substitution pattern. |
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| Keywords: | alkaloids dipolar cycloaddition radical reactions terpenoids total synthesis |
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