Revised Structure of Tolyporphin A |
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Authors: | Thomas G. Minehan,Laura Cook-Blumberg,Yoshito Kishi,Michè le R. Prinsep,Richard E. Moore |
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Abstract: | Four monocyclic precursors were assembled in the total synthesis of the proposed structure 1 - A of (+)-tolyporphin A O,O-diacetate (X=Ac). Comparison of the spectroscopic data demonstrated that synthetic tolyporphin O,O-diacetate did not match the O,O-diacetate prepared from natural (+)-tolyporphin A (X=H), calling for a structural revision of this class of natural products. On the basis of a series of NMR experiments including synthetic intermediates, the structure of tolyporphin A is concluded to be 1 - B , in which the configurations of quaternary centers C7 and C17 are opposite to those in the originally proposed structure. |
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Keywords: | Natural products NMR spectroscopy Porphyrinoids Structure elucidation |
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