Concise Total Syntheses of (-)-Crinipellins A and B Enabled by a Controlled Cargill Rearrangement.
J Am Chem Soc
; 146(31): 21250-21256, 2024 Aug 07.
Article
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| MEDLINE
| ID: mdl-39052841
ABSTRACT
Herein, we report concise total syntheses of diterpene natural products (-)-crinipellins A and B with a tetraquinane skeleton, three adjacent all-carbon quaternary centers, and multiple oxygenated and labile functional groups. Our synthesis features a convergent Kozikowski ß-alkylation to unite two readily available building blocks with all the required carbon atoms, an intramolecular photochemical [2 + 2] cycloaddition to install three challenging and adjacent all-carbon quaternary centers and a 5-6-4-5 tetracyclic skeleton, and a controlled Cargill rearrangement to rearrange the 5-6-4-5 tetracyclic skeleton to the desired tetraquinane skeleton. These strategically enabling transformations allowed us to complete total syntheses of (-)-crinipellins A and B in 12 and 13 steps, respectively. The results of quantum chemical computations revealed that the Bronsted acid-catalyzed Cargill rearrangements likely involve stepwise paths to products and the AlR3-catalyzed Cargill rearrangements likely involve a concerted path with asynchronous alkyl shifting events to form the desired product.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Diterpenos
Idioma:
En
Revista:
J Am Chem Soc
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos