Total Synthesis and Determination of the Absolute Configuration of (+)-Intricatetraol

摘要

Intricatetraol (1), a member of a family of squalene-derived triterpene polyethers named oxasqualenoids,[1] was isolated from the red alga Laurencia intricata by Suzuki et al. in 1993. A crude fraction containing intricatetraol (1) as the major component exhibited cytotoxic activity against P388 leukemia cells with an IC50 value of 12.5 g mL-1.[2] The structural analysis was mainly carried out by NMR spectroscopic methods. Although it was found that the molecule has C2 symmetry, the cis configuration within the tetrahydrofuran ring, the R configuration at C11 (C14), the relative configurations at C6 and C7 (C18 and C19), C10 and C11 (C14 and C15), and at bromine-bonded C3 (C22) remained to be determined.