Quinone epoxides. Part IV. Structure and stereochemistry of mycochrysone

Abstract

Degradative and spectroscopic studies, coupled with evidence from model systems and a stereospecific reduction of the dehydro-compound, have been used to show that the fungal metabolite mycochrysone is r-6′,7′-epoxy-5′,6′-dihydro-4′,5,c-5′-trihydroxy-1,1′-binaphthyl-3,4,8′(7′H)-trione. N.m.r. studies indicate that rotation about the 1,1′-bond is slow and suggest that the energy barrier is close to the limiting value for stable rotational isomers at room temperature. The associated pigments and probable biosynthesis of the compound are discussed.