Abstract
The synthesis of a number of grisa-3′,5′-diene-2′,3-diones by oxidative coupling of substituted 2,2′-dihydroxy-4-methoxybenzophenones is described. The rearrangement of these grisadienediones to depsidones under basic, acidic, and thermal conditions is described and the mechanisms of these reactions are discussed. It is proposed that depsidone biosynthesis involves the oxidative coupling of benzophenones to grisadienediones which then rearrange to depsidones.