Abstract
Stable benzene‐fused polysulfide compounds, 3,4‐dihydro‐1,2,5‐benzotrithiepins (1a‐c), have been prepared, and the structure of 1a has been determined by X‐ray crystallographic analysis. While the electrophilic oxidation of compounds 1 with m‐chloroperbenzoic acid gave the corresponding 3,4‐dihydro‐1,2,5‐benzotrithiepin 5‐oxides (2) in moderate yields, the oxidation of 1 with N‐bromosuccinimide afforded a mixture of 5‐oxides 2, unexpected, inseparable 3,4‐dihydro‐1,2,5‐benzotrithiepin 2,2‐dioxides (3), and 3,4‐dihydro‐1,2,5‐benzotrithiepin 1,1‐dioxides (4). Semiempirical PM3 calculations were carried out, and the computed HOMO of 1a suggested a significant favoring of electrophilic reactions at the sulfur atom at the 5‐position. The treatment of 5‐oxides 2 with acetyl bromide or oxalyl dibromide as halogenating reagents gave 2,2‐dioxides 3 and 1,1‐dioxides 4, suggesting that an intramolecular halogen transfer from the 5‐position (sulfide moiety) to the 1‐ and 2‐positions (disulfide moiety) took place in the reactions.