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

Abstract

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)