Inorganosulfur chemistry, asulfenyl chloride is afunctional group with the connectivityR−S−Cl, where R isalkyl[1] oraryl. Sulfenyl chlorides are reactive compounds that behave as sources ofRS+. They are used in the formation ofRS−N andRS−O bonds. According toIUPAC nomenclature they are named as alkyl thiohypochlorites, i.e.esters of thiohypochlorous acid.
Typically, sulfenyl halides are stabilized byelectronegative substituents. This trend is illustrated by the stability ofCCl3SCl obtained by chlorination ofcarbon disulfide.
Sulfenyl chlorides can be converted tosulfinyl chlorides (RS(O)Cl). In one approach, the sulfinyl chloride is generated in two steps starting with reaction of athiol (−SH) withsulfuryl chloride (SO2Cl2). In some cases the sulfenyl chloride results instead, as happens with 2,2,2-trifluoro-1,1-diphenylethanethiol. Atrifluoroperacetic acid oxidation then provides a general approach to formation of sulfinyl chlorides from sulfenyl chlorides:[12]
Sulfenylfluorides andbromides are also known.[13] Simple sulfenyliodides are unstable with respect to thedisulfide andiodine, gradually decomposing over the course of several hours at low temperature:
2 R−SI → (R−S)2 + I2
They can be formed metastably from metalmercaptides andiodine, and even form fleetingly when iodine oxidizes neutralthiols to the disulfide. Indeed, sulfenyl iodides are believed to be the active iodinating agents iniodotyrosine biosynthesis.[14] Sulfenyl iodides that are heavily sterically hindered from dimerization are stable.[15]
A related class of compounds are the alkylsulfur trichlorides, as exemplified by methylsulfur trichloride,CH3SCl3.[16]
The corresponding selenenyl halides,R−SeCl, are more commonly encountered in the laboratory. Sulfenyl chlorides are used in the production of agents used in thevulcanization of rubber.
^Danehy, James P. (1971). "The Sulfur–Iodine Bond". In Senning, Alexander (ed.).Sulfur in Organic and Inorganic Chemistry. Vol. 1. New York: Marcel Dekker. pp. 331–335.ISBN0-8247-1615-9.LCCN70-154612.
^Sase, S.; Aoki, Y.; Abe, N.; Goto, K. (2009). "Stable Sulfenyl Iodide Bearing a Primary Alkyl Steric Protection Group with a Cavity-shaped Framework".Chemistry Letters.38 (12):1188–1189.doi:10.1246/cl.2009.1188.
^Braverman, S.; Cherkinsky, M.; Levinger, S. (2008). "Alkylsulfur Trihalides".Sci. Synth.39:187–188.ISBN9781588905307.
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