The chlorination of unsymmetrical aliphatic sulfides by N-chlorosuccinimide (NCS) in carbon tetrachloride has been investigated. The resulting mixtures of α-chloro sulfides have beenanalyzedusing nmr spectrometry. The reaction of benzyl t-butyl sulfide and benzyl p-methoxybenzyl sulfide with sulfuryl chloride results in carbonsulfur bond cleavage; reaction of these substrates with NCS affords α-chloro sulfides. Ratios of chlorinated products from the reactions of ethyl methylsulfide with NCS and sulfuryl chloride also indicate significant differences between these chlorinating agents. © 1969, American Chemical Society. All rights reserved.