Selective S-methylation of highly fluorinated thiocarbamates

A series of new S-methyl O-fluoroalkyl N-alkyl(aryl)imidothiocarbonates were prepared by S-methylation of various fluoroalkylated thiocarbamates with methyl iodide in the presence of cesium carbonate and tetrabutylammonium iodide (TBAI) in tetrahydrofuran (THF) at room temperature. As expected from the mostly soft electrophilic alkyl halide (MeI), no isomer products derived from N-methylation were detected. The products were characterized by spectroscopic (1H, 13C and 19F) NMR, infrared, and high-resolution mass spectrometric techniques.