Cesium carbonate-promoted synthesis of aryl methyl sulfides using S-methylisothiourea sulfate under transition-metal-free conditionsElectronic supplementary information (ESI) available: Spectral data, and copies of 1H NMR and 13C NMR spectra of the synthesized compounds. See DOI: 10.1039/c8ob01758a

In the presence of cesium carbonate, an efficient synthesis of aryl methyl sulfides by the reactions of aryl halides with commercially available S -methylisothiourea sulfate is developed. This odourless and highly crystalline solid can be used as the substitute for malodorous methanethiol. The gram-scale reaction also proceeds smoothly without the use of column chromatography separation. Similarly, 2-(dimethylamino)ethylthio and cyclopropylmethylthio groups can be easily introduced into the aromatic rings from the corresponding S -[2-(dimethylamino)ethyl]isothiourea dihydrochloride and S -cyclopropylmethylisothiourea hydrobromide. The possible reaction mechanism is proposed. It is believed that this route to aryl alkyl sulfides is well competitive with currently known methods due to its wide substrate scope, excellent yields, easy operation and transition-metal-free conditions. Odourless and crystalline solid S -methylisothiourea sulfate can be used as the S -source for the synthesis of aryl methyl sulfides.