| Popis: |
A mechanism is suggested for the reaction of 1,2,3,3-tetra-phenylprop-2-en-1-one (1) under the influence of some tungsten compounds containing WO or WC bonds. The processes involved in the polymerization of 1 are described as redistribution of atoms (C, O and W), involving four-membered metallacyclic transition states. The latter can be visualized by the schemes of olefin metathesis, carbonyl-olefin exchange reaction, reductive coupling of carbonyl compounds etc. These conclusions are confirmed by the fact that the processes under investigation can be catalyzed not only by tungsten oxocompounds but also by the stable Casey carbene. |
