Laccase-catalyzed phenol oxidation. Rapid assignment of ring-proton deficient polycyclic benzofuran regioisomers by experimental 1H–13C long-range coupling constants and DFT-predicted product formation

Publikations-Art

Zeitschriftenbeitrag (peer-reviewed)

Autoren

Leutbecher, H.; Greiner, G.;Amann, R.; Stolz, A.; Beifuss, U.; Conrad, J.

Erscheinungsjahr

2011

Veröffentlicht in

Org. Biomol. Chem.

Band/Volume

9/8

DOI

10.1039/c1ob00012h

Seite (von - bis)

2667-2673

Laccase-catalyzed oxidation of substituted catechols followed by reaction with 4-hydroxy-pyrone/-benzopyrone afforded substituted benzofuran regioisomers whose structures with only two aromatic protons in total prevent a rapid structural assignment. Based on the evaluation of ¹H-¹³C long-range coupling constants a rule of thumb could be deduced for an easy and unambiguous differentiation between the possible regioisomers formed. DFT frontier orbital calculations of the reactants offer an interesting tool to explain the regioselectivity of the key reaction.