CpCo(i) precatalysts for [2 + 2 + 2] cycloaddition reactions : Synthesis and reactivity


The efficient synthesis and structural characterisation of a series of novel CpCo(i)-olefin-phosphite/phosphoramidite complexes and their evaluation in catalytic cyclotrimerisation reactions are reported. The protocol for precatalyst synthesis is widely applicable to different P-containing ligands, especially phosphites and phosphoramidites, as well as acyclic and cyclic olefins. A selection of the prepared complexes was investigated towards their catalytic performance in [2 + 2 + 2] cycloaddition reactions of diynes and nitriles, as well as triynes. While revealing significant differences in reactivity, the most reactive precatalysts work even already at 75 °C. One of these precatalysts also proved its potential in exemplary (co)cyclotrimerisations towards functionalised pyridines and benzenes. The energetics of complex formation and exemplary ligand exchange with a substrate diyne were elucidated by theoretical calculations and compared with the catalytic reactivity. © 2020 The Royal Society of Chemistry.

Chelation, Cycloaddition, Ligands, Olefins, Catalytic performance, Catalytic reactivity, Complex formations, Cycloaddition reaction, Efficient synthesis, Ligand exchanges, Phosphoramidites, Theoretical calculations, Synthesis (chemical)
Fischer, F., Pientka, T., Jiao, H., Spannenberg, A., & Hapke, M. (2020). CpCo(i) precatalysts for [2 + 2 + 2] cycloaddition reactions : Synthesis and reactivity (Version publishedVersion, Vol. 10). Version publishedVersion, Vol. 10. London : RSC Publ. https://doi.org//10.1039/d0cy00876a