Horst B, Verdoorn DS, Hennig S, van der Heijden G, Ruijter E. Enantioselective Total Synthesis of (-)-Limaspermidine and (-)-Kopsinine by a Nitroaryl Transfer Cascade Strategy.
Angew Chem Int Ed Engl 2022;
61:e202210592. [PMID:
36004723 PMCID:
PMC9826323 DOI:
10.1002/anie.202210592]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Indexed: 01/11/2023]
Abstract
We report an intramolecular conjugate addition/Truce-Smiles/E1cb cascade of 2-nitrobenzenesulfonamide-functionalized cyclohexenones as a new entry to the core scaffold of monoterpene indole alkaloids. The method was applied to the asymmetric total synthesis of (-)-limaspermidine, (-)-kopsinilam, and (-)-kopsinine, as well as the framework of the kopsifoline alkaloids, thus highlighting its complementarity to existing approaches involving the use of indole-based starting materials or the interrupted Fischer indole synthesis. Furthermore, we show that the cascade tolerates various substituents on the nitroarene, opening the way to other natural products as well as non-natural analogues.
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