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DOI: 10.1055/s-0033-1341098
Total Synthesis of Guttiferone A
Publication History
Publication Date:
17 April 2014 (online)
Key words
polycycles - acylphloroglucinols - decarboxylation - allylation - ring-closing metathesis - ring-opening cross-metathesis
Significance
Similarly to most of the polyprenylated polycyclic acylphloroglucinols, guttiferone A exhibits a bicyclo[3.3.1]nonatrione core. However, in addition to the common endocyclic stereocenters at C1, C5, and C7 found in this class of natural products, guttiferone A possesses an additional stereocenter at C6. Based on their previously reported method for the construction of the core (Nature Chem. 2011, 3, 938), Plietker and co-workers describe a short and diastereoselective synthesis of this compound.
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Comment
1,4-Addition to enone D occurred in high yield and selectively, affording E with the correct relative configuration at C1, C6, and C7. Attempts to directly achieve decarboxylative allylation on E exclusively gave G with the wrong configuration at C5. Consequently, in order to decrease steric interaction of the C6-homoallyl group, bicyclic product H was prepared by ring-closing metathesis. This strategy led to the formation of the desired diastereoisomer I which was then cyclized by Claisen condensation. Finally, cross-metathesis followed by acylation and deprotection afforded the target.
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