Total Synthesis of the Proposed Structure of (+)-Tolyporphin A O,O-Diacetate

✍ Scribed by Thomas G. Minehan; Yoshito Kishi

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 91 KB
• Volume: 38
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/(sici)1521-3773(19990401)38:7<923::aid-anie923>3.0.co;2-7

✦ Synopsis

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.