CARBENE ADDUCTS OF MAGNESIUM AND ZINC

The syntheses and characterizations of adducts of dialkylmagnesium and dialkylzinc with nucleophilic carbenes are described. These carbene a dducts are available directly from the reaction of the stable nucleoph ilic carbenes 1,3-dimesitylimidazol-2-ylidene or 1,3-di(1-adamantyl)im idazol-2-ylidene and the dialkylmetal compounds. The X-ray crystal str uctures of the 1,3-di(1-adamantyl)imidazol-2-ylidene.diethylzinc adduc t and 1,3-dimesitylimidazol-2-ylidene.diethylmagnesium are reported. T he adamantyl substituted carbene gave a monomeric metal adduct whereas the mesityl substituted carbene shows a structure with bridging alkyl groups.