Enantioselective Oxidation of Thioethers. An Improved Route to the Resolution of [1,1′-Binaphthalene]-2,2′-Dithiol

Abstract

(±)-[1,1′-Binaphthalene]-2,2′-bis-methylthioether (±)-1 was oxidized with high enantioselectivity by using our asymmetric reagent [Ti(IV) : (+)-DET : TBHP = 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.