Formation of γ-Lactones by the Reaction of π-Allylnickel Complexes with Carbon Dioxide

Recently, considerable interest has been shown in the reaction of carbon dioxide with olefins or alkynes caused by transition metal complexes. Incorporation of CO2 in oligomerizations of butadiene1) and 1-hexyne2) has been performed to give lactone derivatives by Pd-Ph2 PCH2 CH2 PPh2 and Ni (COD)2-Ph2P(CH2)4PPh2 (COD : 1,5-cyclooctadiene) systems, respectively. Very recently, Jolly et al. reported the reaction of CO2 with π-allylnickel complexes which are the key intermediates of the oligomerization of diolefins.3) For example, bis (η-methylallyl) nickel reacts with CO2 in the presence of a phosphine ligand to give a nickel carboxylate complex: