1835-09-2Relevant articles and documents
Ruthenium-Catalyzed C-C bond cleavage in lignin model substrates
Vom Stein, Thorsten,Den Hartog, Tim,Buendia, Julien,Stoychev, Spas,Mottweiler, Jakob,Bolm, Carsten,Klankermayer, Jürgen,Leitner, Walter
, p. 5859 - 5863 (2015)
Ruthenium-triphos complexes exhibited unprecedented catalytic activity and selectivity in the redox-neutral C-C bond cleavage of the β-O-4 lignin linkage of 1,3-dilignol model compounds. A mechanistic pathway involving a dehydrogenation-initiated retro-aldol reaction for the C-C bond cleavage was proposed in line with experimental data and DFT calculations.
Electroorganic Reactions. 38. Mechanism of Electrooxidative Cleavage of Lignin Model Dimers
Pardini, Vera L.,Smith, Carmen Z.,Utley, James H. P.,Vargas, Reinaldo R.,Viertler, Hans
, p. 7305 - 7313 (2007/10/02)
The mechanisms for oxidative cleavage of several phenolic ethers, models for lignins, have been investigated by a detailed comparison of the results of anodic oxidation at nickel anodes in alkaline electrolyte with that of oxidation in acetonitrile in the presence of a triarylamine redox catalyst.The latter reaction is unambiguously initiated by single-electron transfer (SET), and in this case the major product of cleavage is aldehyde (vanillin or syringaldehyde derivatives).At nickel anodes polymerization is predominant although the aldehydes are formed together with larger amounts of the corresponding carboxylic acids.Combinations of 4-hydroxyl, α-keto, β-O-aryl, and β-hydroxymethyl functionality are shown to be crucial for the oxidation at nickel; the carboxylic acid formation probably involves a route with initial hydrogen atom abstraction at the surface.Important chemical conversions precede and accompany oxidation in alkaline media, and these are associated with the propensity for polymerization.
