The reaction of disulfides or thiols with sodium hypochlorite pentahydrate in acetic acid efficiently provided the corresponding sulfonyl chlorides in high yields.

Synthesis of sulfonyl halides using sodium hypochlorite pentahydrate (NaOCl•5H2O) crystals was studied in detail, considering the reaction rate and yield of the desired product. NaOCl•5H2O reacted with disulfides or thiols in acetic acid to produce sulfonyl chlorides. The yields of the desired sulfonyl chlorides were enhanced when the reaction was performed in (trifluoromethyl)benzene under a CO2 atmosphere. The generation of hypochlomous acid (HOCl) was essential for both reactions. Similarly, sulfonyl bromides were prepared via the reaction of disulfides or thiols with sodium bromide and NaOCl•5H2O crystals in acetic acid owing to the generation of hypobromous acid (HOBr). However, the reaction could not proceed in (trifluoromethyl)benzene under a CO2 atmosphere because bromine (Br2) was produced instead of HOBr.

Oxidation of sulfides with sodium hypochlorite pentahydrate crystals (1.1 equiv) in an aqueous acetonitrile solution selectively produces the corresponding sulfoxides in high yields. This procedure is catalyst-free and environmentally benign.

Crystals. -Oxidation of disulfides or thiols with sodium hypochlorite pentahydrate gives sulfonyl chlorides in an environmentally benign and economical manner. -(OKADA, T.; MATSUMURO, H.; IWAI, T.; KITAGAWA, S.; YAMAZAKI, K.; AKIYAMA, T.; ASAWA, T.; SUGIYAMA, Y.; KIMURA, Y.; KIRIHARA*, M.; Chem. Lett. 44 (2015) 2, 185-187, http://dx.doi.org/10.1246/cl.140899 ; Dep. Mater. Sci., Shizuoka Inst. Sci. Technol., Fukuroi, Shizuoka 437, Japan; Eng.) -B. Mosebach 33-121