The adducts of stabilized enolates and [(q4-1, 3-butadiene) Co (C0) 3] BF4(1) and [(q4-l, 3- cyclohe~ adiene) Co (CO)~] BF~(2) undergo deprotonation and subsequent reactions to form either hydrofurans, cyclopropanes, or cY, P, y, &diunsaturated dicarbonyl derivatives depending upon the reacting complex and the P-dicarbonyl component. All of the observed reactions are strongly promoted by HMPA.
