REACTIONS OF DIMETHYLTITANOCENE WITH ALKYNES AND NITRILES

Thermolysis of dimethyltitanocene in the presence of internal alkynes formed the corresponding titanacyclobutenes cleanly and efficiently. This reaction was shown to be first order in dimethyltitanocene with a primary kinetic isotope effect. When diphenylacetylene was reacted with dimethyltitanocene at lower temperatures, a competitive migratory insertion process took place, forming a vinyl-substituted titanocene species. An analogous reaction with 2 equiv of nitriles formed the known 1,3-diaza-2-titana-1,4-cyclohexadiene derivatives.