摘要:
Four diastereomers of topsentolide C-2, a cytotoxic nine-membered lactone isolated from the marine sponge Topsentia sp., were synthesized stereodivergently from a common chiral seco acid by the combined use of the Yamaguchi and Mitsunobu lactonizations. Comparison of the NMR spectra of the four diastereomers with those of an authentic sample of topsentolide C-2 led to the stereochemical determination of topsentolide C-2 as 8R, 11S, and 12S. (C) 2013 Elsevier Ltd. All rights reserved.