Sulfur—oxygen bonds hydrogen halides

The acidity difference of hydrogen atoms adjacent to divalent sulfur compared to oxygen stems from the greater polarizability of sulfur and the longer C-S-bond length d-orbitals are not involved. In most cases treatment of dithianes with w-BuLi at temperatures of -30 °C is sufficient for the preparation of the lithio-derivatives. With pKA values of approximately 30, lithiated dithianes can react with aldehydes or ketones, epoxides and acid derivatives, but also with alkyl halides without competing elimination reactions. 

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