Diazocarbonyl Compounds in Organofluorine Chemistry

Abstract

AbstractDiazocarbonyl compounds are useful substrates in di- and trifunctionalization reactions based on F/CF3/SCF3 introduction. In the presented reactions, various electrophilic F/CF3/SCF3-transfer reagents were used. The majority of the reactions were based on rhodium catalysis and the application of various oxygen nucleophiles, such as alcohols, cyclic/acyclic ethers, and carboxylic acids. The oxyfluorination reactions were further developed to provide a new fluorine-18 labeling method. Density functional theory (DFT) modeling studies were performed to get a deeper mechanistic understanding of these reactions. These DFT modeling studies indicated that the catalytic reactions proceed through formation of rhodium carbene and oxonium ylide intermediates. The oxonium ylides undergo tautomerization to enol ether type species that subsequently react with the electrophilic F/CF3/SCF3-transfer reagents. We also present an arylation–trifluoromethylthiolation reaction for simultaneous introduction of C–SCF3 and C–C bonds into diazocarbonyl compounds. This reaction does not proceed by rhodium catalysis, but follows a Hooz-type mechanism.1 Introduction2 Diazocarbonyl Compounds: Versatile Substrates in Organic ­Synthesis3 Fluorination, Trifluoromethylation, and Trifluoromethylthiolation of Diazo Substrates3.1 Metal-Free Reactions3.2 Metal-Catalyzed Reactions with Nucleophilic Reagents3.3 Metal-Catalyzed Reactions with Electrophilic Reagents4 Oxyfluorination Reactions4.1 Fluorobenziodoxole as a Fluorine Source4.2 [18F]Fluorobenziodoxole as a Fluorine Source for Radiolabeling4.3 Oxyfluorination with NFSI5 Oxytrifluoromethylation6 Oxytrifluoromethylthiolation7 Arylation–Trifluoromethylthiolation Reaction8 Conclusions and Outlook