Complete 13C-labeling pattern of yessotoxin a marine ladder-frame polyether

Biosynthesis of a marine ladder-frame polyether yessotoxin (YTX) produced by the dinofalgellate Protoceratium reticulatum was investigated. The 13C-labeling experiments indicated that the carbons in YTX were derived from acetates, a methyl of methionine and glycolate, and six-membered ring tetrads (rings A–D and H–K) were constructed from repetition of C3 units (m–m–c), which consisted of a methyl of acetate and acetate.