Zirconocene derivatives, uses

The obvious advantage of our photochemical procedure is that it allows the formation of 3 under mild conditions at very low temperature. Thereby, thermally rather unstable derivatives of 3 may be generated and their reactions studied.- This enabled us, for example, to show that stereochemical configurations at the diene termini are retained during photolysis, but may be lost by subsequent, rather rapid thermally induced intramolecular rearrangement steps. For example, irradiation of 10 in the presence of pure (Z,Z)-2,4-hexadiene at -60°C yields exclusively s-trans-Tj -(Z,Z)-2,4-hexadiene)zirconocene [3h-(Z,Z)]. At -40°C, the stereochemical information at one terminal diene carbon center is lost. A clean... 

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