Catalytic hydration of Alkynes and its application in synthesis

The catalytic addition of water to alkynes (hydration) generates valuable carbonyl compounds from unsaturated hydrocarbon precursors. Traditional mercury(II) catalysts hydrate terminal alkynes with Markovnikov selectivity to methyl ketones. Much research has been devoted to finding catalysts based on less toxic metals, the most promising being gold(I), gold(III), platinum(II), and palladium(II). Catalytic anti-Markovnikov hydration of terminal alkynes to aldehydes has been realized in an efficient manner with ruthenium(II) complex catalysts. The present review article lists known hydration catalysts and discusses applications of catalytic hydration to different classes of substrates, with an emphasis on functional group tolerance and regioselectivity.