ABSTRACT
The Lewis acids MCl3 (M = Fe and Al)-catalyzed electrophilic aromatic (ArH) substitution reactions with thionyl chloride (SOCl2) have been shown to give diaryl sulfoxide (Ar2SO) and the reduced diaryl sulfide (Ar2S). Under various selected conditions, the FeCl3-catalyzed reactions of chlorobenzene gave substantially much higher percent yields of Ar2S (Ar = p-ClC6H4) than the reactions catalyzed by AlCl3, showing that FeCl3 facilitates the reduction in the sulfur center of SOCl2. A dπ −> pπ* back bond between Fe(III) and the O˭S group is thought to be responsible for enhancement of the reduction.
Funding
We would like to thank University of Charleston and its Chemistry Program for financial support.