Asymmetric Total Syntheses and Structure Revisions of Eurotiumide A and Eurotiumide B, and Evaluation of their Fluorescent Properties as Natural Probes
Nakayama, Atsushi Tokushima University Tokushima University Educator and Researcher Directory KAKEN Search Researchers
Sato, Hideo Tokushima University
Karanjit, Sangita Tokushima University Tokushima University Educator and Researcher Directory
Hayashi, Naoki Kyoto Pharmaceutical University
Oda, Masataka Kyoto Pharmaceutical University
Namba, Kosuke Tokushima University Tokushima University Educator and Researcher Directory KAKEN Search Researchers
Asymmetric total syntheses and structure revisions of dihydroisocoumarin-type natural products, eurotiumide A and eurotiumide B have been described. The key features of these total syntheses are the asymmetric Shi epoxidation, regio and stereo-selective epoxide opening, C1 insertion/lactonization cascade reaction for constructing 4-methoxyisochroman-1-one skeleton. We confirmed the structures and configurations of eurotiumide A and B on the basis of X-ray crystallographic analysis of the key intermediate, and revealed that eurotiumide A and B have cis and trans configurations at H3/H4 positions, which are the opposite relationship of the stereochemistry from the previous report, respectively. The absolute configurations of them are also determined. These natural products exhibited highly fluorescence in several solvents with large Stokes shifts involving the excited-state intramolecular proton transfer mechanism, which is supported by time-dependent density functional theory. Eurotiumide A also emitted fluorescence in Bacillus cereus.
European Journal of Organic Chemistry
This is the peer-reviewed version of the following article: Nakayama, A. , Sato, H. , Karanjit, S. , Hayashi, N. , Oda, M. and Namba, K. (2018), Asymmetric Total Syntheses and Structure Revisions of Eurotiumide A and Eurotiumide B, and Their Evaluation as Natural Fluorescent Probes. Eur. J. Org. Chem., 2018: 4013-4017, which has been published in final form at https://doi.org/10.1002/ejoc.201800535. This article may be used for non-commercial purposes in accordance with Wiley-VCH Terms and Conditions for Self-Archiving.
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