Copper sulfoxide complexes

Kwart and Kahn have found that benzenesulfonyl azide forms a complex with freshly reduced copper powder.189 190 This copper azide complex decomposes at a lower temperature than the pure sulfonyl azide. In refluxing methanol, benzene-sulfonamide (27) is isolated as the major product. In the presence of dimethyl sulfoxide, N-benzenesulfonyldimethyl-sulfoximine (28) is obtained in almost quantitative yield. In cyclohexene solution benzenesulfonamide (29), N-benzenesul-fonyl-7-azabicyclo[4.1.0]heptane (30), and 1-cyclohexenylben-zenesulfonamide (31) are isolated as the main reaction products. According to the authors, Schemes VII and VIII represent an acceptable interpretation of the experimental data.189 190 In pure alcohol, the decomposition should occur by two competitive reactions (Scheme VII) producing benzenesulfonamide together with a ketone and oxidized copper. These last two products have indeed been observed in the reaction mixture. In the presence of DMSO, it seems that a copper-nitrene intermediate is formed which is trapped by DMSO. In cyclohexene solution, the authors have observed that the aziridine (30) disappears from the product composition when DMSO is added. The yield of enamine 31, however, is... 

Copper(II) complex (5) catalyses the oxidation of sulfides to sulfoxides with hydrogen peroxide in high yields. Addition of a catalytic amount of TEMPO to the reaction mixture enhances the conversion and selectivity.181... 

Ruano, J. L. G., De la Plata, B. C. Asymmetric [4+2] cycloadditions mediated by sulfoxides. Topics in Current Chemistry 1999, 204,1-126. Johnson, J. S., Evans, D. A. Chiral Bis(oxazoline) Copper(ll) Complexes Versatile Catalysts for Enantioselective Cycloaddition, Aldol, Michael, and Carbonyl Ene Reactions. Acc. Chem. Res. 2000, 33, 325-335. 

Several copper-catalyzed 7 -arylation reactions of imidazole have been published. The coupling of arylboronic acids with imidazole in the presence of binuclear bis-p,-hydroxy copper (11) complexes in air has been carried out at ambient temperature without the need for base <04TL7659>. A variety of A -arylimidazoles were prepared in excellent yields through the cross-coupling of arylboronic acids with imidazole in methanol or water with copper(I) chloride <04CC188>. Copper(II) oxide-coated nanoparticles were used catalytically in the Ullmann coupling of imidazole with various aryl chlorides with cesium carbonate in dimethyl sulfoxide <04CC778>. 

Copper(II) dimethyl sulfoxide complexes [Cu(Me2SO) ] + [ra = 4 (309, 391) n = 5 (496) n = 9 (221)] have been synthesized and assigned as O-bonded by spectroscopic study. The Ph2SO complex [Cu(Ph2SO)4] + (228) has been prepared and isolated as its perchlorate salt. Preliminary crystallographic data (320) and ESR data (483) are available which suggest D41, symmetry for the metal-ion site. 

Complexes of metal + ligand + protein or DNA can also catalyze the Diels Alder cycloaddition or oxidations with hydrogen peroxide. Copper complexes bound to DNA catalyzed the Diels-Alder cycloaddition with up to 99% ee [15, 16], Cu(phthalocyanine) complexed to serum albumin also catalyzed the enantioselective (98% ee) Diels-Alder reaction, but only with very high catalyst loading (10 mol%) and only with pyridine-bearing dienophiles (presumably to complex the copper) [17]. Achiral Cr(III) complexes or Mn(Schiff-base) complexes inserted into the active site of apomyoglobin variants catalyzed the sulfoxidation of thio-anisole with up to 13 and 51% ee, respectively [18, 19]. A copper phenanthroline complex attached to the adipocyte lipid-binding protein catalyzed the enantioselective hydrolysis of esters and amides [20]. 

Trilialophenols can be converted to poly(dihaloph.enylene oxide)s by a reaction that resembles radical-initiated displacement polymerization. In one procedure, either a copper or silver complex of the phenol is heated to produce a branched product (50). In another procedure, a catalytic quantity of an oxidizing agent and the dry sodium salt in dimethyl sulfoxide produces linear poly(2,6-dichloro-l,4-polyphenylene oxide) (51). The polymer can also be prepared by direct oxidation with a copper—amine catalyst, although branching in the ortho positions is indicated by chlorine analyses (52). 

Copper-mediated coupling of the aryl iodide derived from l,3-bis(2-hydroxy-hexafluoroisopropyl)benzene with perfluorooctyl iodide gives the desired compound as a dimethyl sulfoxide (DMSO) complex [166] (equation 143) Even bromoarenes can be coupled [167] (equation 144)... 

Whereas acyclic sulfoxides form complexes with various metal salts, thiirane oxides react with copper(II) chloride or bromide163 in benzene at room temperature to give the thiolsulfonate 146a. In alcoholic solution below 0 °C the major products are sulfinates (149). Similar results are obtained in the reaction of thiirane oxides with ethanesulfinyl chloride163 as summarized in equation 60. 

Different metal complexes have shown the ability to catalyze these imination reactions, such as rhodium, copper, and iron.22 In 2005, Bolm found that the disilver(I) complex described in Section 6.2.2 catalyzes the imination of sulfides and sulfoxides... 

Oxidation of sulfur compounds. The copper(lI) nitrate complexed with dimerizes thiols to afford disulfides and oxidizes sulfides to sulfoxides. 

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