Abstract The nickel (1) complex, Ni (teta)+, formed by cathodic reduction of the corresponding nickel (11) complex, reacts rapidly with alkyl bromides to form an unstable intermediate containing a nickel carbon bond. When the electrolysis medium also contains an activated olefin an insertion reaction occurs. The new metal carbon bond is cleaved by further reduction and overall the reduction of Ni (teta) 2+ in the presence of RBr and CH 2 ...