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Sequencing palladium-catalyzed cycloisomerization cascades in a synthesis of the gelsemine core.

ABSTRACT: Transition metal-catalyzed cycloisomerization is a powerful strategy for the construction of cyclic organic molecules, and the use of palladium catalysts can deliver a wide range of monocyclic and bicyclic products. However, applications of cycloisomerizations in complex target synthesis in which more than one cycloisomerization process is deployed in a cascade context are rare. Here we report investigations of the relative rates of two different types of ene-ynamide cycloisomerization that form fused and spirocyclic rings, and use of these results to design a sequence-controlled cascade cycloisomerization that prepares the tetracyclic core of gelsemine in a single step. Crucial to this work was an evaluation of the kinetics of each cycloisomerization in competition experiments, which revealed a key influence of the ynamide electron-withdrawing group on the cycloisomerization reaction.

SUBMITTER: Liang G

PROVIDER: S-EPMC10306092 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature

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Sequencing palladium-catalyzed cycloisomerization cascades in a synthesis of the gelsemine core.

Liang Guoduan G Anderson Edward A EA

Chemical science 20230605 25

Transition metal-catalyzed cycloisomerization is a powerful strategy for the construction of cyclic organic molecules, and the use of palladium catalysts can deliver a wide range of monocyclic and bicyclic products. However, applications of cycloisomerizations in complex target synthesis in which more than one cycloisomerization process is deployed in a cascade context are rare. Here we report investigations of the relative rates of two different types of ene-ynamide cycloisomerization that form ...[more]

PMID: 37389268

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