Implications for the Existence of a Heptasulfur Linkage in Natural o-Benzopolysulfanes

Natural o-benzopolysulfanes are often thought to exist as either the trisulfane or pentasulfane; the nomenclature has evolved around such notions. No study makes reference to the possible existence of natural o-benzoheptasulfanes. The work performed here indicates that a facile equilibration takes place between the tri-, penta-, and heptasulfanes (o-C 6 H 4 S 3 , o-C 6 H 4 S 5 , and o-C 6 H 4 S 7 ) in solution. In these simpler (unnatural) compounds, the number of sulfur atoms can be established unequivocally from their independent syntheses. The o-benzopolysulfanes, even after purification, yield mixtures of compounds in solution. A similar equilibration may be anticipated for the corresponding natural products.