Absolute configuration at C45 in 45-hydroxyyessotoxin, a marine polyether toxin isolated from shellfish.

The marine polyether toxin, 45-hydroxyyessotoxin, was Isolated together with yessotoxin from the scallop, Patinopecten yessoensis. The 45-hydroxy group in the gide chain was esterified with (S)- and (R)-alpha-methoxy-alpha-trifluoromethylphenylacetic acids (MTPA). A detailed analysis of the 2D NMR spectra of the two esters established the R configuration at C45.