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Updated: Jan 10, 2026

Biosynthesis of a Flavonol from a Flavanone by Establishing a One-pot Bienzymatic Cascade
Published on: August 14, 2019
Total Synthesis and Absolute Configuration Revision of Biofloranate F
Shinnosuke Okazaki1, Madoka Oashi1, Koichiro Ota1
1School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
Abstract:
This paper describes the first total synthesis and absolute configuration revision of biofloranate F, a biflorane-type diterpenoid isolated from the soft coral Lemnalia bournei. The synthesis involved an intramolecular Diels-Alder (IMDA) reaction to form the cis-fused decalin core. A key step was an Evans asymmetric alkylation to introduce an asymmetric center with high stereocontrol while guiding the stereoselectivity of subsequent steps, including the pivotal IMDA reaction. Although the spectroscopic data of the initially synthesized product matched those of the natural compound, its specific rotation was opposite. This discrepancy prompted us to synthesize its enantiomer, which exhibited identical characteristics to those of the natural product. Consequently, the absolute configuration of biofloranate F was unequivocally revised to 5S, 6R, 9S, 10R, and 11S.
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