Electrosynthesis of sulfur-containing organic fluorine compounds from trifluoromethyl-substituted cumulene derivatives using a sacrificial sulfur–graphite electrode

Abstract

Electrosynthesis of organic polysulfides from cumulenes having two trifluoromethyl groups was studied using a sacrificial sulfur–graphite electrode. The reaction with these cumulenes led to dimeric compounds with a 1,2,5,6-tetrathiocin skeleton as the major product, accompanied with 7- and 8-membered ring compounds with five and six sulfur atoms such as pentathiepins and hexathiocins in minor amounts. These dimeric compounds will be produced by further reaction of the intermediate products such as 7- and 8-membered ring compounds with the polysulfide anion(s). These cyclic compounds will be formed by a Michael addition of the polysulfide anion(s) (S 8 2− and/or S 6 2−) produced by electroreduction of elemental sulfur. Coulometric n-values were less than 1 e per molecule of the cumulene in spite that it needs 2 e or above per half molecules of the dimeric compound.