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Total Synthesis of (+)-Davidiin


  • We thank Prof. Tsutomu Hatano (Okayama University (Japan)) for identification of natural davidiin. We also thank Dr. Yasuko Okamoto (Tokushima Bunri University) for the recording of FAB mass spectra. Kakenhi and a SUNBOR grant partially supported this work.


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Quite strained: The total synthesis of (+)-davidiin, an ellagitannin with more substituents in axial than in equatorial positions, requires a conformational lock of the glucose, induced by steric repulsion between adjacent bulky silyloxy groups. This conformational lock played a pivotal role in 1) the β-selective formation of the glycosyl ester at the anomeric position, 2) the formation of the 1,6-HHDP bridge, and 3) the complete control of axial chirality in the aryl–aryl coupling.