Coupling reactions of a cyclopentadienyl (Cp) ligand with a dienyl or alkenyl ligand on dienyl- or alkenyltitanocenes proceeded to give dienylcyclopentadiene or alkenylcyclopentadiene derivatives in good to high yields. Dienyltitanocene derivatives were prepared by protonation of bis(cyclopentadienyl)titanacyclopentadienes with carboxylic acids. Chlorodienyltitanocene derivatives were formed by the
Anti van't Hoff/le Bel compound 1 consisting of titanocene tolan and diethylborane units reacts with ethene, acetylenes, phosphaacetylenes, and acetone to give metallacycles 2, 3, 6, and 7, and in most cases the corresponding diethylorganylboranes are formed by hydroboration of the carbon-carbon or carbon-heteroatom multiple bond in the substrate. With nitriles the new bimetallic systems 9a-c (X-ray structure available for 9a) with titanium and boron centers and 12 containing zirconium and aluminium centers are generated by the formal insertion of the nitrile into the B-C-planar bond of 1 or the Al-C-planar bond of 11.