An extensive kinetic study of selected key reactions of (oxidative) gold catalysis concentrates on the decrease of the catalytic activity due to inhibition of the gold(I) catalyst caused by pyridine derivatives that are obtained as by-products if N-oxides are applied as oxygen donors. The choice of the examined pyridine derivatives and their corresponding N-oxides has been made regardless of their commercial availability; particular attention has been paid to the practical benefit which up to now has been neglected in most of the reaction screenings. The test reactions were monitored by GC and 1 H NMR spectroscopy. The received reaction constants provide information concerning a correlation between the electronic structure of the heterocycle and the catalytic activity. Based on the collected kinetic data, it was possible to develop a basic set of three N-oxides which have to be taken into account in further oxidative gold(I)-catalyzed reactions.

A selection of gold-catalyzed reactions was examined in a kinetic study on the influence of water on the rate constant. Two intramolecular reactions and one intermolecular reaction, which proceed via proton transfer and/or protodeauration steps, were investigated. The kinetic data was collected by GC or 1 H NMR spectroscopy. The obtained rate constants provided information about the influence of water in these test reactions. On the basis of the data collected, beyond the commonly assumed tolerance against water, a reaction-promoting influence of water on gold catalysis was identified and kinetically quantified. The results underline that the often-mentioned water-tolerance of gold catalysis not only simplifies these reactions operationally, but in addition even provides better results than a troublesome exclusion of water.

The synthesis of aryl amines via the formation of a C−N bond is an essential tool for the preparation of functional materials, active pharmaceutical ingredients and bioactive products. Usually, this chemical connection is only possible by transition metal‐catalyzed reactions, photochemistry or electrochemistry. Here, we report a metal‐free arene C−H amination using hydroxylamine derivatives under benign conditions. A charge transfer interaction between the aminating reagents TsONHR and the arene substrates enables the chemoselective amination of the arene, even in the presence of various functional groups. Oxygen was crucial for an effective conversion and its accelerating role for the electron transfer step was proven experimentally. In addition, this was rationalized by a theoretical study which indicated the involvement of a dioxygen‐bridged complex with a “Sandwich‐like” arrangement of the aromatic starting materials and the aminating agents at the dioxygen molecule.

Despite the widespread use of anilines, synthetic challenges to these targets still exist. Selectivity is often an issue, when using the traditional nitration-reduction sequence or more modern approaches, including arene C–H aminations catalyzed by transition metals, photosensitizers, or electrodes. Accordingly, there is still a need for general methods to rapidly, directly access specific isomers of substituted anilines. Here, we report a simple route towards the synthesis of such motifs starting from benzyl alcohols, which are converted to anilines by the use of arylsulfonyl hydroxylamines, via an aza-Hock rearrangement. Good to excellent yields are observed. The method is applicable to various benzyl alcohol surrogates (such as ethers, esters, and halides) as well as simple alkylarenes. Functionalizations of pharmaceutically relevant structures are feasible under the reaction conditions. Over ten amination reagents can be used, which facilitates the rapid assembly of a vast set of compounds.

Stabilized by a bulky N-heterocyclic carbene [ BP DPr, 1,3-bis(2,6diisopropylphenyl)-1,3-diazonine-2-ylidene] ligand, new silver carboxylate complexes of the form BP DPrAgO 2 C-R (R = Me, Ph) have been synthesized and fully characterized in solution and in the solid state and implemented as sole catalysts (base-, additive-, and, in some cases, solvent-free) in the challenging fixation of carbon dioxide to unsubstituted propargylic derivatives for the synthesis of oxazolidinones and α-methylene cyclic carbonates. Derived from X-ray diffraction studies, the molec-ular geometry and the concept of buried volume were employed to describe the structural and steric features of these silver complexes. Their stability and efficiency as catalysts have been demonstrated by the synthesis of 29 carboxylation products (72-98 % yield) at low catalyst loadings (0.01-1.5 mol%). Characteristics are high turnover numbers (up to 9400), catalyst recyclability (up to 96 % yield after the 7th cycle with no decomposition of the silver complex), and the possibility to scale-up the reaction.