Catalytic isomerization of allyl alcohols to carbonyl compounds using poisoned Pd nanoparticles

This article shows that Pd nanoparticles (NPs) poisoned by alkanethiolate monolayers can catalyze the isomerization of allyl alcohols to the corresponding carbonyl compounds in a relatively high efficiency and with a high selectivity. Pd nanoparticles are produced by the borohydride reduction of K2PdCl4 in toluene/H2O using sodium S-dodecylthiosulfate as a source for the alkanethiolate ligands. Both kinetic and thermodynamic effects control the catalytic reactions of various substituted allyl alcohols. In general, less substituted allyl alcohols including prop-2-en-1-ol and pent-1-en-3-ol are isomerized to the corresponding aldehyde or ketone more efficiently. More substituted allyl alcohols such as but-2-en-1-ol and 3-methylbut-2-en-1-ol do not undergo isomerization under the same condition. However, the presence of reactive, less substituted allyl alcohols is found to promote the isomerization of poorly reactive, more substituted allyl alcohols.

Isomerization over hydrogenation of allyl alcohols using poisoned Pd nanoparticles.Figure optionsDownload high-quality image (79 K)Download as PowerPoint slideHighlights
► Sodium S-alkylthiosulfate (Bunte salts) generates less densely packed alkanethiolate monolayers on Pd nanoparticle surface.
► Pd nanoparticles poisoned by alkanethiolate catalyze selective isomerization over hydrogenation of allyl alcohols.
► Both kinetic and thermodynamic effects control the catalytic reactions of substituted allyl alcohols.