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Total Synthesis of the Claimed Structure of (±)-Hyptinin and Structural Revision of Natural Hyptinin

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journal contribution
posted on 19.04.2017, 13:18 by Kazuto Maeda, Toshiyuki Hamada, Satoaki Onitsuka, Hiroaki Okamura
A total synthesis of (±)-hyptinin was achieved via a convergent route using the key phosphonate, cyclic ketone, and aryl Grignard components. The 1H and 13C NMR spectra of natural hyptinin did not agree with those of the synthesized compound. In particular, there were considerable differences between the signals assigned to the protons and carbons surrounding the lactone carbonyl group for the natural and synthesized compounds. The NMR data strongly suggested that the naturally occurring compound, hyptinin, was a structural isomer of the synthesized compound. The structure of the natural compound was eventually established as (+)-β-apopicropodophyllin, based on the synthesis results.