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Total Synthesis of the Proposed Structure of (+)‐Tolyporphin A O , O ‐Diacetate
Author(s) -
Minehan Thomas G.,
Kishi Yoshito
Publication year - 1999
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/(sici)1521-3773(19990401)38:7<923::aid-anie923>3.0.co;2-7
Subject(s) - chemistry , stereochemistry , total synthesis , crystallography
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.