Volume 60, Issue 52 pp. 27236-27240
Communication

Synthesis of (±)-Setigerumine I: Biosynthetic Origins of the Elusive Racemic Papaveraceae Isoxazolidine Alkaloids**

Ana V. Serna

Ana V. Serna

Department of Chemistry, Rice University, 6500 Main Street, Houston, TX, 77030 USA

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Prof. Dr. László Kürti

Corresponding Author

Prof. Dr. László Kürti

Department of Chemistry, Rice University, 6500 Main Street, Houston, TX, 77030 USA

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Dr. Juha H. Siitonen

Corresponding Author

Dr. Juha H. Siitonen

Department of Chemistry, Rice University, 6500 Main Street, Houston, TX, 77030 USA

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First published: 27 October 2021
Citations: 16
**

A previous version of this manuscript has been deposited on a preprint server (https://doi.org/10.33774/chemrxiv-2021-m9ltg).

Graphical Abstract

The first synthesis of (±)-Setigerumine I, an isoxazolidine Papaveraceae alkaloid, is realized through a biomimetic strategy. The synthesis sheds light to the possible biosynthetic origins of these elusive natural product family members.

Abstract

The biosynthetic origins of the structurally related racemic isoxazolidine Papaveraceae alkaloids Setigerumine I, Dactylicapnosinine and Dactylicapnosine have remained elusive since their original isolation over two decades ago. Herein we report the first biosynthetic hypothesis for their formation and, inspired by it, the first synthesis of (±)-Setigerumine I with accompanying computational rationale. Based on the results, these isoxazolidine alkaloids arise from racemizing oxidative rearrangements of prominent isoquinoline alkaloids Noscapine and Hydrastine. The key steps featured in this synthesis are a room temperature Cope elimination and a domino oxidation/inverse-electron demand 1,3-dipolar cycloaddition of an axially chiral, yet configurationally unstable, intermediate. The work opens this previously inaccessible family of natural products for biological studies.

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