Interaction of Multiple Bonds with NacNacGa: Oxidative Cleavage vs Coupling and Cyclization

The reactivity of the gallium(I) compound NacNacGa (4) to a variety of unsaturated compounds has been studied. Whereas 4 proved surprisingly unreactive toward olefins, ketones, guanidines, and thioureas, it reacts with isocyanates and carbodiimides to furnish the products of coupling of two heterocumulenes. With isothiocyanate, the C═S cleavage occurs, leading to the dimer (NacNacGa)