Brefeldin-A, an antibiotic fungal metabolite, has been obtained in both racemic and natural forms through a direct approach that employs norbornenone and 6-heptyn-2-ol as the basic starting materials.Brefeldin-A (as decumbin) was first isolated in 1958 from Penicillium decumbens by Singleton, Bohonos, and Ullstrup.13 The metabolite has subsequently been found in cultures of Penicillium cyaneum,lh Penicillium brefeldianum,lc and Ascochyta imperfecta,ld as well as in those of a wide variety of other organisms.16"1 The identity1*1•2 3of the metabolites, however, has not in all cases been immediately apparent, thus producing for this compound the names cyanein15 and ascotoxin,1*1 in addition to decumbin13 and brefeldin-A.lc Work1•2 on the elucidation of the structure and stereochemistry, carried out over 14 years, was