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Amine oxidation is an important organic reaction for the production of high-value N-containing compounds. However, it is still challenging to control the reactivity of active N-centered radicals to selectively access N-oxidation products. Herein, this study reports the engineering of cytochrome P450BM3 into multifunctional N-oxidizing enzymes with the assistance of dual-functional small molecules (DFSM) to selectively produce N-oxygenation (i.e., p-nitrosobenzene, p-nitrobenzene, and azoxybenzene) and one-electron oxidation products (i.e., oligomeric quinones and azobenzene) from aromatic amines. The best mutant, F87A/T268V/V78T/A82T, exclusively gives p-nitrosobenzene (up to 98% selectivity), whereas the selectivity for p-nitrobenzene is >99% using the mutant F87A/T268V/A82T/I263L. Crystal structure analysis reveals that key mutations and DFSM exert synergistic effects on catalytic promiscuity by controlling the substrate orientation in active center. This study highlights the potential of DFSM-facilitated P450 peroxygenase and peroxidase for the synthesis of N-containing compounds via the controllable oxidation of aromatic amines, substantially expanding the chemical space of P450 enzymes., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

A cyclic alkyl(amino)carbene (CAAC)-stabilized dicoordinate aminoborylene is synthesized by the twofold reduction of a [(CAAC)BCl 2 (TMP)] (TMP=2,6-tetramethylpiperidyl) precursor. NMR-spectroscopic, X-ray crystallographic and computational analyses confirm the cumulenic nature of the central C=B=N moiety. Irradiation of [(CAAC)B(TMP)] (2) resulted in an intramolecular C-C bond activation, leading to a doubly-fused C 10 BN heterocycle, while the reaction with acetonitrile resulted in an aryl migration from the CAAC to the acetonitrile nitrogen atom, concomitant with tautomerization of the latter to a boron-bound allylamino ligand. One-electron oxidation of 2 with CuX (X=Cl, Br) afforded the corresponding amino(halo)boryl radicals, which were characterized by EPR spectroscopy and DFT calculations. Placing 2 under an atmosphere of CO afforded the tricoordinate (CAAC,CO)-stabilized aminoborylene. Finally, the twofold oxidation of 2 with chalcogens led, in the case of N 2 O and sulfur, to the splitting of the B-C CAAC bond and formation of the 2,4-diamino-1,3,2,4-dichalcogenadiboretanes and CAAC-chalcogen adducts, whereas with selenium a monomeric boraselenone was isolated, which showed some degree of B-Se multiple bonding., (© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Multiple steps are needed to achieve the C-H functional of aromatic aldehyde, since the C-H functional reaction usually occurs preferentially at the aldehydic C-H bond over the aryl C-H bond. We report an efficient azidation method mediated by dirhodium(II) catalysts to achieve the direct aryl azidation of aromatic aldehydes avoiding the simultaneous use of protected aldehydes and prefunctionalized arenes. The regioselectivity of this method is similar to those of typical aromatic electrophilic substitution reactions. The resulting azidobenzaldehyde products are versatile building blocks or precursors for the synthesis of many biologically active compounds. The mechanism studies indicate that the one-electron oxidative intermediate Rh 2 (II,III) N 3 is responsible for the azide transfer., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Oxidation is one of the deterioration reactions of proteins in food, the importance of which is comparable to others such as Maillard, lipation, or protein-phenol reactions. While research on protein oxidation has led to a precise understanding of the processes and consequences in physiological systems, knowledge about the specific effects of protein oxidation in food or the role of "oxidized" dietary protein for the human body is comparatively scarce. Food protein oxidation can occur during the whole processing axis, from primary production to intestinal digestion. The present review summarizes the current knowledge and mechanisms of food protein oxidation from a chemical, technological, and nutritional-physiological viewpoint and gives a comprehensive classification of the individual reactions. Different analytical approaches are compared, and the relationship between oxidation of food proteins and oxidative stress in vivo is critically evaluated., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The synthesis and X-ray structure of a new manganese(V) mesitylimido complex with a tetraamido macrocyclic ligand (TAML), [Mn V (TAML)(N-Mes)] - (1), are reported. Compound 1 is oxidized by [(p-BrC 6 H 4 ) 3 N] +. [SbCl 6 ] - and the resulting Mn VI species readily undergoes H-atom transfer and nitrene transfer reactions., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

One-electron oxidation of 1,4,2,5-diazadiborinine 1 has been studied. While the reaction of 1 a bearing phenyl groups on the B atoms with AgAl{OC(CF 3 ) 3 } 4 afforded a complex mixture, the same oxidation reaction with 1 b featuring bulky mesityl substituents on the B atoms rendered the corresponding cation radical 2 b as an isolable species. X-ray diffraction analysis, EPR spectroscopy, and DFT calculations of 2 b revealed the delocalization of the unpaired electron over the entire π-system of 2 b, as well as a large spin density (0.76 in total) on the two equivalent boron atoms. The chemical trapping reaction of 2 b with p-benzoquinone and triphenyltin hydride afforded the dicationic species 3 containing two newly formed B-O bonds and the monocationic product 2b-H containing a B-H bond, respectively, thus confirming the boron-centered radical reactivity of 2 b., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report the synthesis of a series of ruthenium complexes supported by the phosphine olefin ligand tropPPh2 (trop=5-H-dibenzo-[a,d]cyclohepten-5-yl) in the oxidation states 0, +I, and +II, formed via successive one-electron oxidization steps from Ru(0) (tropPPh2 )2 . The bidentate character of the tropPPh2 ligand and its steric hindrance force the complexes to adopt uncommon geometries, which were investigated by X-ray diffraction analysis. EPR data of the mononuclear Ru(I) complex reveal couplings of the unpaired spin with the ruthenium and two phosphorus nuclei, as well as the olefinic protons which show that the spin is mainly localized on the Ru(I) center., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The oxidation of a Ni(II) complex bearing a tetradentate phosphasalen ligand, which differs from salen by the presence of an iminophosphorane (PN) in place of an imine unit, was easily achieved by addition of a silver salt. The site of this oxidation was investigated with a combination of techniques (NMR, EPR, UV/Vis spectroscopy, X-ray diffraction, magnetic measurements) as well as DFT calculations. All data are in agreement with a high-valent Ni(III) center concentrating the spin density. This markedly differs from precedents in the salen series for which oxidation on the metal was only observed at low temperature or in the presence of additional ligands or anions. Therefore, thanks to the good electron-donating properties of the phosphasalen ligand, [Ni(Psalen)](+) represents a rare example of a tetracoordinated high-valent nickel complex in presence of a phenoxide ligand., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)