海葵毒素全合成.pdfVIP

Pure Appl. Chem.,Vol. 61,No. 3,pp. 313-324, 1989. Printed in Great Britain. @I1989IUPAC Natural products synthesis : palytoxin Yoshito Kishi Department of Chemistry, Harvard University, Cambridge, MA 02138, U.S.A. Abstract. The first part of this presentation is concerned with conformational analysis of C - and 0-saccharides. A useful model for predicting the solution conformation of these classes of compounds is presented. The second part is concerned with the total synthesis of palytoxin carboxylic acid with focus on the bond formation at the C.7-(2.8, C.51-C.52, and C.75-C.76 positions. Palytoxin, the toxic principle isolated from marine soft corals of the genus Palyrhoa, is the most poisonous substance known to date except for a few naturally occurring proteins found in bacteria and plants (ref. 1). The gross structure of palytoxin was elucidated in 1981 by two groups independently, the one led by Professor Hirata at Nagoya in Japan (ref. 2a) and the other by Professor Moore at Honolulu in the United States (ref. 2b). Thus, it is evident that palytoxin is uniquely distinct from molecules, with which organic chemists have previously dealt, in terms of magnitude of molecular size and of structural complexity. Shortly after the gross structure became available, we decided to undertake investigations on this extraordinary natural product; our interests were primarily two-fold, chemical s