Stereoselective hydrogenation of lignin degradation model compounds

Article abstract of DOI:10.1139/v97-149

Di-μ-chloro-bis(η⁴-1,5-hexadiene)dirhodium(I) in a two-phase hexane-aqueous medium catalyzes the diastereoselective H₂-hydrogenation of lignin degradation model compounds 4-propylphenol, 2-methoxy-4-propylphenol, and 2,6-dimethoxy-4-propylphenol. The all-cis diastereomer is obtained selectively when the phenolic hydroxy group is protected as a methyl ether or when a model compound possessing two methoxy substituents adjacent to the phenolic hydroxy group is used. The relative stereochemistries of the hydrogenated products are established by X-ray crystal structure analysis and (or) ¹H NMR.