The absolute configuration of fusaproliferin, a toxic metabolite produ
ced by Fusarium proliferatum, was determined by the combined use of H-
1 NMR and distance geometry. The configuration of double bonds has bee
n determined in agreement with NOESY buildup data. An R configuration
for C10 was determined using Mosher's method. Processing the constrain
ts obtained from NOESY experiments with a distance geometry program, a
limited number (80) of possible structures was derived. An agglomerat
ive nonhierarchical method of clustering was used in order to place th
ese structures into classes suggested by the data, and not previously
defined in any way. This statistical method showed that indeed the str
uctures could be grouped in four classes. One of these classes is repr
esented by a single structure, with the highest sum of violations and
was discarded. All other structures have the same chirality; respectiv
ely S for C14 and R for C15. In solution the overall conformation is q
uite well defined in the region of the five-member ring and the planes
of double bonds C2-C3 and C11-C12, while near to C8 and C9 internal f
lexibility appears evident.