Research On The Synthesis Of A Few Sulfonium Salts

This paper is focused on the alkylation reaction of sulfide with 2-halocarbonyl compounds affording sulfonium salts. 2-Bromo-1-phenylethanone, 2-bromo-1-(4'-fluoro)-phenylethanone, 2-bromo- 1-(4'-acetoxyl)-phenylethanone, 2-bromo-1-(2'-methoxyl)-phenylethanone, 2- bromo-1-furan-2-yl-ethanone, and so on were chosen as substrates reacting with dimethyl sulfide to afford sulfonium salts. After some screening, it was found that this reaction could be realized at ambient conditions, usually at room temperature. Solvent screening using 2-bromo-1-phenylethanone as substrate revealed that this reaction is favored in polar solvents such as methanol and acetone. The reactivity of 2-halo-1-phenylethanone increases from chlorides to iodides. Yields of iodides could reach up to 90%. The reaction of dimethyl sulfide in ethyl ether with different halides revealed a decrease of rates with increasing of chain length and increasing of branching. In addition, the comparison of 2-halocarbonyl compounds with simple halides was also studied.Electronic properties of substitution on the substrates was examined and analyzed. Generally, EWG increase the reaction rates, and vise versa. Steric hindrance on sulfides detains their reactions with 2-bromo-1-phenylethanone.