Unprecedented facile reactions of propane and cycloalkanes with elemental sulfur leading to dialkylsulfides and dicycloalkylsulfides

Abstract

The transformations of propane and cycloalkanes into dialkyl (dicycloalkyl) sulfides under the action of elemental sulfur were achieved for the first time under very mild conditions. Sulfur is converted completely into dicylclopentylsulfide in the reaction with cyclopentane in the presence of CX 4 · nAlBr 3 (X = Cl, Br; n = 2 or 3) at −20°C for 20 min. Propane forms 1Pr 2S in 60% yield at 20°C after 2 h. Sulfurization of adamantane occurs in the presence of the milder electrophilic system CH 2Br 2AlBr 3 at 20°C to afford approximately equal amounts of Ad 2S isomers and 1-AdSMe with the overall yield of sulfurization products of 60%.