Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

Hajdin I, Pajkert R, Keßler M, Han J, Mei H, Röschenthaler G-V. Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups. Beilstein Journal of Organic Chemistry . 2023;19:541-549.A synthetic route to the bench-stable fluorinated masked carbene reagent diethyl 2-diazo-1,1,3,3,3-pentafluoropropylphosphonate, bearing a trifluoromethyl and a difluoromethyl group is reported for the first time. Its application in CuI-catalyzed cyclopropanation reactions with aromatic and aliphatic terminal alkenes under mild reaction conditions is demonstrated. In total, sixteen new cyclopropanes were synthesized in good to very good yields. Copyright © 2023, Hajdin et al

Ru-Catalyzed Hydrogen Atom Transfer/C-F Bond Cleavage of Difluoroalkyl Diazos with Hantzsch Ester via a Photocatalytic Radical Process

Wang Q, Liu J, Mei H, et al. Ru-Catalyzed Hydrogen Atom Transfer/C-F Bond Cleavage of Difluoroalkyl Diazos with Hantzsch Ester via a Photocatalytic Radical Process. Organic Letters. 2022;24(43):8036-8040.A Ru-catalyzed reaction of difluoroalkyl diazo compounds with Hantzsch ester under visible light to achieve the formation of alpha-fluorovinylphosphonates via a radical process has been developed. Mechanistic experiments and density functional theory calculations reveal that the generation of a carbon radical is directly through the hydrogen atom transfer (HAT) by Hantzsch ester. This system represents the first example of generation of carbon radicals from diazo compounds via Hantzsch-ester-assisted HAT and also demonstrates a new radical-involved pathway for the difluoroalkyl diazo compounds

Synthesis and Characterization of Oxazaborinin Phosphonate for Blue OLED Emitter Applications

A blue‐light emitting material based on a boron complex containing heteroaromatic phosphonate ligand is synthesized and characterized. The Phospho‐Fries rearrangement is used in the synthesis route of the ligand as a convenient method of introducing phosphonate groups into phenols. Structural, thermal and photophysical properties of the resulting oxazaborinin phosphonate compound have been characterized. DFT geometry optimizations were studied as well as the spatial position and symmetry of the HOMO and LUMO. Good thermal stability up to 250 °C enables vacuum deposition methods next to solution processing. Combining the work function with the optical band gap from UV‐Vis measurements shows that band alignment is possible with standard contact materials. Photoluminescence reveals an emission peak at 428 nm, which is suitable for a blue light‐emitter