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    Enantioselective Oxidation of Thioethers . An Improved Route To the Resolution of [1,1'-binaphthalene]-2,2'-dithiol

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    (+/-)-[1,1'-Binaphthalene]-2,2'-bis-methylthioether (+/-)-1 was oxidized with high enantioselectivity by using our asymmetric reagent [Ti(IV) : (+)-DET : TBBP = 1 : 4 : 2]. An appropriate substrate/oxidant ratio afforded such a product distribution that allowed us to obtain, after chromatographic separation and chemical transformations, optically pure [1,1'-binaphthalene]-2,2'-dithiol in ca. 80% yield based on the racemic starting material

    The first chiral zirconium(IV) catalyst for highly stereoselective sulfoxidation

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    Partially-hydrolized chiral Zr(IV) catalysts, based on C3 symmetric trialkanolamine ligands 1a-c in the presence of cumyl hydroperoxide, provide a new homogeneous system for the enantioselective sulfoxidation of a wide range of aryl alkyl sulfides. Ee’s in the range 80-90% are obtained, through the cooperative effect of two independent stereoselective processes, namely the direct asymmetric oxidation of the sulfide to the sulfoxide and its subsequent kinetic resolution to sulfone, allowing the recover of the desired product with yields up to 35%. In every reaction the peroxide is converted quantitatively with as little as 2% of catalys
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