Laccase-catalyzed dimerization of glycosylated lignols

Publication date: Available online 2 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Ivan Bassanini, Paolo Gavezzotti, Daniela Monti, Jana Krejzová, Vladimír Křen, Sergio Riva Phenylpropanoid glucosides (PPGs) are naturally occurring and bioactive phenolic derivatives, largely distributed in plants. In this work different PPGs have been chemically or enzymatically synthesized from the lignols coniferyl and p-coumaryl alcohols as substrates for a laccase-catalyzed oxidative coupling. The biooxidation of these PPGs has been investigated here and novel dihydrobenzofuran-based structurally modified analogues have been isolated and characterized. Specifically, the presence of a carbohydrate moiety increased the water solubility of these compounds and reduced the number of dimeric products, as pinoresinol-like structures could not be formed. Looking for a possible sugar-promoted stereochemical enrichment of the obtained diastereomeric mixtures of dimers, different carbohydrate moieties (D-glucose, L-glucose and the disaccharide rutinose) were considered and the respective d.e. values of the dimeric products were measured by 1H NMR and HPLC. However, it was found that the sugar substituent had a minor effect on the stereochemical outcome of the radical coupling reactions, the best measured result being a d.e. value of 21%. Graphical abstract

Source: Journal of Molecular Catalysis B: Enzymatic - November 1, 2016 Category: Biochemistry Source Type: research