Stoichiometric carbon-carbon bond formation mediated by well defined Nb(III) complexes

The Nb(III) complex (BDI)Nb(NtBu)(CO)2 reacts with two equivalents of t-butylacetylene to form a metal-bound yne-one-ene moiety resulting from coupling of CO to two equivalents of the terminal alkyne. Additionally, Z-alkene and α,β-unsaturated imine formation from hydrogenolysis of an internal alkyne bound complex in the presence of an isocyanide ligand is described. 65