Selective Catalytic Formation of Cross-Tetramers from Tetrafluoroethylene, Ethylene, Alkynes, and Aldehydes via Nickelacycles as Key Reaction Intermediates

In the presence of
a catalytic amount of Ni­(cod)2 (cod
= 1,5-cyclooctadiene) and PCy3 (Cy = cyclohexyl), the cross-tetramerization
of tetrafluoroethylene (TFE), ethylene, alkynes, and aldehydes leads
to a variety of fluorine-containing enone derivatives. This reaction
is the first example of a highly selective cross-tetramerization between
four different unsaturated compounds. Stoichiometric reactions revealed
that the present reaction involves partially fluorinated five- and
seven-membered nickelacycles as key reaction intermediates.