Synfacts 2018; 14(09): 0887
DOI: 10.1055/s-0037-1609605
Synthesis of Natural Products and Potential Drugs
© Georg Thieme Verlag Stuttgart · New York

Total Synthesis of (±)-Salimabromide

Contributor(s):
Erick M. Carreira
,
Niels Sievertsen
Schmid M. Grossmann AS. Wurst K. Magauer T. * Ludwig-Maximilians-University Munich, Germany and University of Innsbruck, Austria
Total Synthesis of Salimabromide: A Tetracyclic Polyketide from a Marine Myxobacterium.

J. Am. Chem. Soc. 2018;
140: 8444-8447
Further Information

Publication History

Publication Date:
20 August 2018 (online)

 

Significance

Unlike their terrestrial counterparts, myxobacteria of marine origin have remained ­underexplored by the scientific community. ­Recently, the polyketide antibiotic salimabromide was isolated from obligate marine myxobacterium Enhygromyxa salina. Magauer’s team mastered the challenges associated with the preparation of this structurally demanding and biologically potent secondary metabolite. Pivotal in their approach to this bridged tetracycle were a Wagner–Meerwein rearrangement/Friedel–Crafts cyclization, a [2+2] cycloaddition, and a Baeyer–Villiger reaction.


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Comment

The authors commenced with the ­expedient preparation of ketone C from m-anis­aldehyde and pinacolone. Following epoxidation and treatment with catalytic acid, Wagner–­Meerwein rearrangement and cyclization were ­effected, furnishing primary alcohol D. This intermediate was further elaborated to amide G. The ketiminium derived from G underwent [2+2] cycloaddition to furnish H in excellent yield. Ultimately, allylic oxidation, Baeyer–Villiger reaction, and dibromination of the arene afforded (±)-salimabromide. An asymmetric route to intermediate D has been devised by the authors as well.


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