Sulfoxides with ceric ammonium nitrate

Startg. m. (prepared from 1,4-diphenylbutane and hexacarbonylchromium) treated with K-tert-butoxide in dimethyl-dg sulfoxide followed by oxidative decomplexa-tion with ceric ammonium nitrate l,l-dideuterio-l,4-diphenylbutane. Y 70%. Also partial replacement of benzylic protons s. W. S. Trahanovsky and R. J. Card, Am. Soc. 94, 2897 (1972). 

Silyl enol ethers can be dimerized to symmetrical 1,4-diketones by treatment with Ag20 in dimethyl sulfoxide or certain other polar aprotic solvents.465 The reaction has been performed with R2, R-1 = hydrogen or alkyl, though best yields are obtained when R2 = R1 = H. In certain cases, unsymmetrical 1,4-diketones have been prepared by using a mixture of two silyl enol ethers. Other reagents that have been used to achieve either symmetrical or cross-coupled products are iodosobenzene-BFy-EtiO.466 ceric ammonium nitrate,467 and lead tetraacetate.m If R1 = OR (in which case the substrate is a ketene silyl acetal), dimerization with TiCL, leads to a dialkyl succinate (32, R1 = OR).4 9... 

Ceric ammonium nitrate (1.10 g, 0.002 mol) is added in one portion to a stirred solution of 0.093 g (0.0005 mol) of diphenyl sulfide in 8 mL of 75% aqueous acetonitrile. After 3 min at room temperature, the mixture is quenched with 5 mL of water, and the product is obtained by extraction with two 20-mL portions of ether and evaporation of the solvents. Diphenyl sulfoxide, mp 68-70 °C, is obtained in 82% yield. 

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