Science of Synthesis

Mikami, K.; Matsumoto, Y.; Shiono, T., Science of Synthesis, (2003) 2, 531.

Titanium–diene complexes, such as, ‌154‌ (‌Scheme 79‌) have been reviewed.[‌293‌] In (s-cis-di­ene)metal complexes, usually found in the early transition-metal complexes, the bonding of the diene ligand has pronounced σ2,π-metallacyclopentane character, in contrast to the η4-diene structure found in the late transition metals. The σ2,π-metallacyclopentane form corresponds to a formal oxidative addition of the diene to the metal center; this renders the terminal carbon atoms on the diene nucleophilic. As a result, these compounds are very versatile: they can behave either as metallacyclopentene complexes or as metal–diene complexes, depending on the nature of the substrate. Structural analyses of both prone (endo) and supine (exo) conformations of complexes ‌154‌ have been reported (‌Scheme 79‌).[‌294‌]

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References

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• 8.Meeeee-Meee, (8888) M 88-8, 888.