Stoichiometric Use of the Butadiene Metallocenes

Similarly, the coupling of two conjugated dienes has been reported to take place at CpTi-derived complexes to yield linear C8-products.94 

Bis(aryloxy)Ti(butadiene) systems react with a variety of a-olefins to form linear C6-coupling products.95 

Vinyloxiranes react with the Negishi-reagent [Cp2ZrBu2] by means of deoxygenation to yield conjugated dienes. This reaction is likely to 

Nitriles react with (butadiene)zirconocenes in similar ways however, some important details of the reaction course are different in these cases. A variety of aryl-, hetaryl-, or alkylcyanides add cleanly to the [(butadiene) ZrCp2] reagent. It is likely that 92 is the initial CC-coupling product. Under typical reaction conditions this is not stable but rapidly undergoes a tautomerization reaction to yield the isomer 93. This can rapidly react further with a second equivalent of the nitrile reagent to 

The conjugated primary enamines 95 exhibit planar frameworks with alternating C=C double and C-C single bonds between their C(sp2) atoms. Conjugation extends through the C(NH2) center to the attached aryl ring systems which generally are oriented close to coplanar with the 

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