Stereochemical assignment of the fungal metabolite xestodecalactone A by total synthesis

The first synthesis of the macrocyclic natural product xestodecalactone A, a metabolite of a sponge-derived fungus, is described. By the use of methyl 5-hydroxyhexanoate in its R- or S-configured form, or as its racemate as the precursors, both enantiomers of xestodecalactone A as well as the racemic compound were obtained. Comparison of these synthetic products with the natural product by circular dichroism (CD) spectroscopy and by HPLC on a chiral phase revealed the natural product to have the (R)-configuration.