ASYMMETRIC OXIDATION OF THIOETHERS. OPTICAL RESOLUTION OF -2,2'-DITHIOL

Article abstract of DOI:10.1016/S0040-4039(01)80454-8

Almost optically pure (e.e.>98percent) <1,1'-binaphthalene>-2,2'-dithiol (2) is obtained by resolution of racemic 2 via the transformation of the sulfidryl functions into the corresponding thioethers 3 which are asymmetrically oxidized to diastereomeric chiral monosulfoxides 4 and then reconverted into 2.The diastereo and enantioselectivity is dependent on the structure of the thioether; i.e. the dimethylthioether 3a gives two diastereomeric sulfoxides 4a in ca. 1:1 ratio, each of them in >98percent e.e., while cyclic dithioethers 3b-d afford a single diastereomeric sulfoxide 4b-d in 46-78percent e.e..