Hydration of Propargylic Alcohols by Ruthenium Catalysts, with Dominant Anti-Markovnikov Regioselectivity, Formation of α,β-Unsaturated Products and Catalytic Decarbonylation to 1-Alkenes

Ruthenium catalysts — water-soluble ruthenium sulfophthalocyanine and heterogeneous ruthenium hydroxyapatite complexes — proved to be effective for the hydration of propargylic alcohols in entirely aqueous media. 1-Phenyl-2-propyn-1-ol underwent an unprecedented catalytic hydration-decarbonylation-dehydration reaction, giving rise to styrene and carbon monoxide; 2-propyn-1-ol and 3-butyn-2-ol gave predominantly the products of anti-Markovnikov addition, together with products of hydration-dehydration (α,β-rearrangement) and, to a minor extent, the decarbonylation products, ethene or propene, respectively. Hydrations were also conducted in D2O, giving indications of the mechanism of the reactions and apparently ruling out the allenylidene route for the α,β-rearrangement. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)