Exceptional Substrate Diversity in Oxygenation Reactions Catalyzed by a Bis(μ‐oxo) Copper Complex.

Paul, Melanie; Teubner, Melissa; Grimm‐Lebsanft, Benjamin; Golchert, Christiane; Meiners, Yannick; Senft, Laura; Keisers, Kristina; Liebhäuser, Patricia; Rösener, Thomas; Biebl, Florian; Buchenau, Sören; Naumova, Maria; Murzin, Vadim; Krug, Roxanne; Hoffmann, Alexander; Pietruszka, Jörg; Ivanović‐Burmazović, Ivana; Rübhausen, Michael; Herres‐Pawlis, Sonja

The enzyme tyrosinase contains a reactive side‐on peroxo dicopper(II) center as catalytically active species in C−H oxygenation reactions. The tyrosinase activity of the isomeric bis(μ‐oxo) dicopper(III) form has been discussed controversially. The synthesis of bis(μ‐oxo) dicopper(III) species [Cu2(μ‐O)2(L1)2](X)2 ([O1](X)2, X=PF6−, BF4−, OTf−, ClO4−), stabilized by the new hybrid guanidine ligand 2‐{2‐((dimethylamino)methyl)phenyl}‐1,1,3,3‐tetramethylguanidine (L1), and its characterization by UV/Vis, Raman, and XAS spectroscopy, as well as cryo‐UHR‐ESI mass spectrometry, is described. We highlight selective oxygenation of a plethora of phenolic substrates mediated by [O1](PF6)2, which results in mono‐ and bicyclic quinones and provides an attractive strategy for designing new phenazines. The selectivity is predicted by using the Fukui function, which is hereby introduced into tyrosinase model chemistry. Our bioinspired catalysis harnesses molecular dioxygen for organic transformations and achieves a substrate diversity reaching far beyond the scope of the enzyme.

OXYGENATION (Chemistry); PHENOL oxidase; MASS spectrometry; CHEMICAL models; CATALYSIS

Chemistry - A European Journal, 2020, Vol 26, Issue 34, p7556

0947-6539

Academic Journal

10.1002/chem.202000664