Three symmetric substances originating from triethyl phosphate were specifically synthesized with varying degree of fluorination at the side chain. Different concentrations of each phosphate were evaluated as co-solvent with regard to their flammability and the electrochemical cycling performance. With higher degree of fluorination and a higher amount of the phosphate in the electrolyte, the self-extinguishing time (SET), a value to determine and compare the flammability of electrolytes, could be significantly lowered to yield a non-flammable electrolyte mixture. A specifically designed SET device is introduced, which offers more accurate results due to lowered standard deviations by minimizing random and systematic errors. As the application of phosphates as co-solvents results in a trade-off in cycling performance, a thorough determination in regard to the ionic conductivity, the anodic oxidation stability and the compatibility with anode and cathode material was carried out in half- and full-cells. The manuscript strives to establish a deeper understanding of the influence that the utilization of phosphates as co-solvents entail with special focus on the fluorination degree. It could be shown that the partially fluorinated phosphate offers the best cycling results and therefore the lowest trade-off in performance, while a severe improvement in SET could be achieved compared to the reference electrolyte.

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For almost 40 years, difluoromethylene phosphonates have proven to be versatile molecular tools in biochemical studies owing to their close resemblance to naturally occurring phosphates and phosphonates. As bioisosteric, non‐hydrolyzable analogs of these essential molecules, difluoromethylene phosphonates can target the critical parts of the cellular machinery and therefore exhibit a diverse spectrum of biological activity. In the past ten years, there have appeared many new methods for the synthesis of difluoromethylene phosphonates. Most notably, photoredox catalysis has firmly entered the field, while cross‐coupling and nucleophilic strategies have met considerable elaboration and refinement, entirely in accord with the current trends in synthetic organic chemistry. Herein, we introduce difluoromethylene phosphonates as a distinct, high‐tech subclass of synthetic phosphonates resulting from the research efforts on the cross‐section of organophosphorus, organofluorine, and bioorganic chemistry. We then proceed to the discussion of general methods for the preparation of difluoromethylene phosphonates, comprehensively reviewing reactions developed in the past 15 years while providing the context of earlier works where appropriate. Finally, we present selected examples of molecules with high biological activity, their biological targets, and the synthetic steps employed for their preparation.

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Enantiomerically pure N,O-protected b-trifluoromethyl isoserine derivatives of (2S,3S)-and (2R,3S)-absolute configurations have been easily prepared by diastereoselective addition of the enolates, derived from O-protected a-hydroxyacetates, to (S)-N-tert-butanesulfinyl (3,3,3)-trifluoroacetaldimine with high combined yield and good syn/anti stereoselectivity. To explain the unusual stereochemical outcome in these reactions a mechanistic rationale involving the addition of Z-enolates to (S)-imines via open transition states was proposed on the basis of the experimental data. Elaboration of these products via chemoselective manipulation of the protecting groups has been demonstrated.