Efficient recyclable catalytic system for deoxygenation of sulfoxides: catalysis of ionic liquid-molybdenum complexes in ionic liquid solution

Deoxygenation of Sulfoxides to Sulfides with Thionyl Chloride and Triphenylphosphine: Competition with the Pummerer Reaction

“…The deoxygenation of sulfoxides to the corresponding sulfides is a fundamental and significant functional group transformation in organic synthesis. During the last few decades, many types of methods have been developed to reduce sulfoxides. − Among them, a variety of metal complexes including molybdenum (Mo), − rhenium (Re), ,− zinc (Zn), − samarium (Sm), , iron (Fe), copper (Cu), niobium (Nb), − and other metals − have been widely employed for the deoxygenation of sulfoxides. Other reagents such as phosphorus compounds, − cyanuric chloride, triflic anhydride, acid chloride, , and halogen molecules as activators were also used.…”

NaSH-HCl mediated reduction of sulfoxides into sulfides under organic solvent-free reaction conditions

“…in the presence of electrophilic bromine as catalyst (19), mercaptopropyl-functionalized silica gel in the presence of 2% of Mo catalyst in toluene (20), PPh 3 (1.1 eq.) in the presence of 5 mol% of ionic-liquid-molybdenum complexes in ionic liquid/toluene (21), NaHSO 3 (1.1 eq. )/10 mol% of I 2 in chloroform (22), catecholborane (2 eq.…”

Efficient reduction of sulfoxides with NaHSO 3 catalyzed by I 2

“…The reaction of dibenzyl sulfoxide with NaHSO 3 in CHCl 3 in the absence of I 2 did not proceed (Table 1, entry 9). Furthermore, the reaction of dibenzyl sulfoxide (1 mmol) and NaHSO 3 (1.1 mmol) in CHCl 3 at 50 °C was also studied (Table 1, entries [14][15][16]. In the absence of I 2 , the reaction did not proceed (Table 1, entry 14).…”

“…Recently reported methods for the deoxygenation of sulfoxides include oxalic acid/titanium(IV) oxide, 6 alcohols/hydroxyapatite-supported ruthenium nanoparticles, 7 silanes or boranes/oxo-rhenium(V) complexes, 8 PPh 3 /SOCl 2 , 9 iron powder/H 2 CO 3 , 10 glycerol/dioxomolybdenum(VI) complexes, 11 boranes/zinc, 12 pinacol/molybdenum catalysts, 13 thioacetic acid/I 2 , 14 PPh 3 /ionic liquid molybdenum complexes, 15 silica bromide, 16 NbCl 5 /indium, 17 NaI/silica sulfuric acid 18 and oxo-rhenium complexes. 19 However, some of these processes are limited by side reactions, low yields, and expensive reagents and catalysts, or harsh reaction conditions.…”