Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid

Abstract

The synthesis of thioethers starting from alcohols and thiols in the presence of amorphous solid acid catalysts is reported. A silica alumina catalyst with a very low content in alumina gave excellent results in terms of both activity and selectivity also under solvent-free conditions. The reaction rate follows the electron density of the carbinol atom in the substrate alcohol and yields up to 99% and can be obtained for a wide range of substrates under mild reaction conditions.

Pd/PTABS: Low-Temperature Thioetherification of Chloro(hetero)arenes

“…(Figure ). Traditional synthetic approaches to prepare thioethers are numerous but suffer from drawbacks such as long reaction times, moderate reactivities, and poor results with aryl thiols synthons. − …”

Copper catalyzed reaction of alcohols, alkyl halides and Na2S2O3: an odorless and ligand-free route to unsymmetrical thioether synthesis

“…As expected, most of the alcohol remained intact in DMSO because alkyl halide was mainly converted to the undesired 1,2-diisopentyldisulfane by oxidation of the corresponding in situ generated thiol (Table 1, entry 15). The effects of the amount of catalyst on the reaction were next examined (Table 1, entries 19,20). Reducing the amount of catalyst to 5 mol% increased the reaction yield to 90% by reducing the amounts of side-products (Table 1, entry 19).…”

“…18 Also, Santoro et al discovered a catalyzed method for direct C-S cross-coupling of thiols with alcohols in the presence of amorphous solid acid catalysts leading to thioethers. 19 Another process for the synthesis of unsymmetrical sulfides via a three-component reaction of alcohols, organohalides, and sodium thiosulfate under strongly acidic conditions was reported by Wang and Ji. They treated an alkyl halide (0.5 mmol) with anisyl alcohol (1 mmol) and Na 2 S 2 O 3 (1.5 mmol) in the presence of HCl (0.5 mmol) at 100 1C for 12 h to obtain thioethers mostly in moderate yields.…”

“…18 Also, Santoro et al discovered a catalyzed method for direct C–S cross-coupling of thiols with alcohols in the presence of amorphous solid acid catalysts leading to thioethers. 19…”

Multicomponent Solvent-Free Synthesis, Antibacterial Evaluation and QSAR Study of 2-(Bis(benzylthio)methylene) malononitriles

“…8 New methods and procedures were developed to synthesize organic sulfides. For this purpose, metal-catalyzed reactions, [9][10][11] Sandmeyer and Leuckart reactions, 12,13 coupling of thiols with Grignard reagents in the presence of N-chlorosuccinimide, 14 photocatalytically initiated thiol-ene reaction, 15 free radical displacement on alkynes, 16 regioselective conjugate addition of thiols to acyclic α,β,γ,δ-unsaturated dienones, 17 in situ nucleophilic substitution of aryl bromides with potassium iodomethyltrifluoroborates, 18 displacement reaction of halogens by sulfur, 19 Stevens rearrangement of thioethers with arynes, 20 and synthesis of thiiranes via reaction of epoxides with thiourea in DES 21 were proposed by researchers. Alkylation of thiols or their salts is a well-developed method for the preparation of thioether derivatives.…”