Chemo-Enzymatic Metathesis/Aromatization Cascades for the Synthesis of Furans: Disclosing the Aromatizing Activity of Laccase/TEMPO in Oxygen-Containing Heterocycles

The unprecedented Trametes versicolor laccase/TEMPO-catalyzed aromatization of 2,5-dihydrofurans to furans is described. A variety of furan derivatives have been synthesized in moderate to high conversions (21–99%) and yields (20–76%) under mild reaction conditions. This work reveals the aromatization ability of the Trametes versicolor laccase/TEMPO system in synthesizing oxygen-containing heterocycles. Moreover, the direct synthesis of furans from aliphatic diallyl ethers through a chemo-enzymatic metathesis/aromatization cascade, which combines Grubbs-catalyzed ring-closing metathesis and laccase/TEMPO-catalyzed aromatization in the same reaction medium, has been successfully developed.