[structure: see text] A new strategy that extends the application of the J-based configuration analysis to systems characterized by multiple conformer equilibria is described and applied to sapinofuranone A (1), a phytotoxic molecule produced by three strains of Sphaeropsis sapinea. This method, based on a combination of computational techniques and NMR spectroscopy, uses ab initio calculations to predict a set of theoretical homo- and heteronuclear J values which can be compared against experimental NMR data.