Organocuprate (R2Cu-) reagents react with a carbon electrophile to form a new C-C bond, yet their silver and gold counterparts seldom serve for such purposes. The origin of this striking difference is discussed with the aid of the quantum mechanical calculations using hybrid density functional method. The copper reaction takes place through two steps, the nucleophilic reaction of the ate complex R2Cu(I)(-) with an electrophile E+ and the decomposition of the resulting R-2(E)Cu(III) intermediate. These two steps were examined for Cu, Ag, and Au to find the reasons for the superiority of organocopper compounds to the silver and the gold counterparts. The first reaction is favored because of the higher-lying d-orbitals that directly participate in the nucleophilic reaction. The second reaction is faster with copper because of the intrinsic instability of the high valent copper species.