Facile Access to AgOCF3 and Its New Applications as a Reservoir for OCF2 for the Direct Synthesis of N-CF3 , Aryl or Alkyl Carbamoyl Fluorides

The development of innovative fluorination strategies is greatly dependent also on the availability, safety and practicability of available fluorinating reagents. We herein show a straightforward and quantitative strategy for the preparation of valuable AgOCF₃ at room temperature and showcase its performance in trifluoromethoxylations or as reservoir for O=CF₂ . This enabled the direct, practical and safe synthesis of valuable N-alkyl/aryl and N-CF₃ carbamoyl fluorides from secondary amines and isothiocyanides, respectively. Our mechanistic data indicate that AgOCF₃ does not liberate O=CF₂ until it is activated by a nucleophilic co-reagent, reinforcing the stability of the salt under our new preparation strategy.

Access to Cyclic N-Trifluoromethyl Ureas through Photocatalytic Activation of Carbamoyl Azides

We report the mild activation of carbamoyl azides to the corresponding nitrenes using a blue light/[Ir]-catalyzed strategy, which enables stereospecific access to N-trifluoromethyl imidazolidinones and benzimidazolones. These novel structural motifs proved to be highly robust, allowing their downstream diversification. On the basis of our combined computational and experimental studies, we propose that an electron rebound with the excited metal catalyst is undergone, involving a reduction-triggered nitrogen loss, followed by oxidation to the corresponding carbamoyl nitrene and subsequent C-H insertion.

Machine Learning-Guided Development of Trialkylphosphine Ni(I) Dimers and Applications in Site-Selective Catalysis

Owing to the unknown correlation of a metal's ligand and its resulting preferred speciation in terms of oxidation state, geometry, and nuclearity, a rational design of multinuclear catalysts remains challenging. With the goal to accelerate the identification of suitable ligands that form trialkylphosphine-derived dihalogen-bridged Ni^(I) dimers, we herein employed an assumption-based machine learning approach. The workflow offers guidance in ligand space for a desired speciation without (or only minimal) prior experimental data points. We experimentally verified the predictions and synthesized numerous novel Ni^(I) dimers as well as explored their potential in catalysis. We demonstrate C-I selective arylations of polyhalogenated arenes bearing competing C-Br and C-Cl sites in under 5 min at room temperature using 0.2 mol % of the newly developed dimer, [Ni^(I)(μ-Br)PAd₂(n-Bu)]₂, which is so far unmet with alternative dinuclear or mononuclear Ni or Pd catalysts.