Categories: S-H Bond Formation >
Reduction of sulfoxides
1,3,5-Triazo-2,4,6-triphosphorine-2,2,4,4,6,6-tetrachloride (TAPC) is an efficient promoter for the oxidation of sulfides and deoxygenation of sulfoxides. Excellent yields, short reaction time, easy and quick isolation of the products, solvent-free process, and excellent chemoselectivity are the main advantages of this procedure.
K. Bahrami, M. M. Khodaei, M. S. Arabi, J. Org. Chem., 2010, 75, 6208-6213.
The combination of triflic anhydride and potassium iodide was an effective promoter for the deoxygenation of sulfoxides and gave the corresponding sulfides in excellent yield in acetonitrile at room temperature. This reagent system is chemoselective and tolerates various functional groups, such as alkenes, ketones, esters, aldehydes, acids, and oximes.
K. Bahrami, M. M. Khodaei, A. Karimi, Synthesis, 2008, 2543-2546.
Sodium borohydride in the presence of iodine in anhydrous THF converts various sulfoxides to their thioethers in excellent yields. A chemoselective deoxygenation of sulfoxides can be achieved in the presence of other reducible functional groups such as esters, nitriles and double bonds.
B. Karimi, D. Zareyee, Synthesis, 2003, 335-336.
In a mild reduction of sulfoxides, sulfides are obtained in excellent yields when aliphatic and aromatic sulfoxides were treated with SOCl2 as a catalyst and Ph3P in THF at room temperature.
Y. Jang, K. T. Kim, H. B. Jeon, J. Org. Chem., 2013, 78, 6328-6331.
A dichlorodioxomolybdenum(VI)-catalyzed oxotransfer allows a chemoselective deoxygenation of sulfoxides to sulfides in the presence of P(OPh)3 as the stoichiometric reductant.
R. Sanz, J. Escribano, R. Aguado, M. R. Pedrosa, F. J. ArnŠiz, Synthesis, 2004, 1629-1632.
Various alkyl and aryl sulfoxides have been successfully deoxygenated using 3-mercaptopropionic acid as a reducing agent and a catalytic amount of either NBS or I2 in MeCN at ambient temperature. Under the described reaction conditions, acid sensitive substrates such as acetals remained intact.
B. Karimi, D. Zareyee, Synthesis, 2003, 1875-1877.
Sulfoxides and aza-aromatic N-oxides were deoxygenated using a system of indium and pivaloyl chloride at room temperature to give the corresponding sulfides and aza-aromatics in high yields.
E. S. Park, S. Hwan, Lee, J. H. Lee, H. J. Rhee, C. M. Yoon, Synthesis, 2005, 3499-3501.