diastereomeric models (3a and 3b) corresponding to the CDE/FG ring of prymnesins, polycyclic ether toxins isolated from the red tide phytoflagellate Prymnesium parvum, is described. Comparison of the (1)H and (13)C NMR data for each compound with those reported for prymnesins suggests that the earlier stereochemicalassignment of the E/F ring juncture needs to be revised.
Convergent synthesis of the BCDEFGHIJ-ring polyether core of gambieric acids, potent antifungal polycyclic ethers
作者:Kazushi Sato、Makoto Sasaki
DOI:10.1016/j.tet.2007.02.039
日期:2007.6
A convergent synthesis of the nonacyclic BCDEFGHIJ-ring polyether core of gambiericacids, potent antifungal polycyclic ether marine natural products, has been achieved. The present synthesis involved as key features: (i) convergent union of the BCD- and GHIJ-ring fragments through esterification, (ii) construction of the E-ring as a lactone form via reductive acetylation, (iii) stereoselective allylation