Thioketal

As thioketal (more precisely: dithioketals ) is called in chemistry a ketal in which both the acetal oxygen atoms were replaced by sulfur atoms. In Monothioketalen only one of the two acetal oxygen atoms of the ketal is replaced by a sulfur atom.

Today thioketals usually be subsumed under the term thioacetals, although the former are derived from ketones and not of aldehydes.

Synthesis

For the synthesis of a thioketal, a ketone under acid catalysis with a mono-or divalent or thioalcohol in the presence of zinc chloride with elimination of water. Alternatively, thioacetals are first deprotonated with a base at the Corey -Seebach reaction. The anion thus formed yields in the subsequent reaction with an alkyl halide, the corresponding thioketal:

Use

The oxidation of thioketals provides disulfones reduction with Raney nickel alkanes.