trans-1,2-Dichlorocyclohexane from the interaction of benzenesulphonyl chloride and cyclohexene in the presence of aluminium chloride

Abstract

Under Friedel–Crafts conditions where acyl halides react with alkenes to provide β-chloro-ketones or products of their dehydrochlorination and rearrangement, benzenesulphonyl chloride and cyclohexene fail to provide the analogous β-chloro-sulphone but instead give an approximately equimolar mixture of benzenesulphinic acid and trans-1,2-dichlorocyclohexane. Best yields are obtained by using carbon disulphide as solvent and sulphonyl chloride–catalyst ratios greater than 1 : 1. When cyclohexene is replaced by ethylene, reduction of the sulphonyl chloride to benzenesulphinic acid appears to be the main reaction, but in this instance the neutral product is a complex mixture of low-molecular-weight polymeric material containing chlorine. Under similar conditions trichloroethylen fails to react.