1,2‐Addition of Diethylzinc to a Bis(Imidazolyl)ketone Ligand

In this study, the selective 1,2‐addition of diethylzinc to the ketone functionality of BM(diPh)IK [bis(1‐methyl‐4,5‐diphenylimidazolyl)ketone] is shown. The reaction product is isolated in a dimeric form with a planar Zn(2)(µ‐O)(2)‐motif keeping the two monomers together. This compound can serve as a model for reactive intermediates in the catalytic alkylation of ketones with diorganozinc reagents. Hydrolysis of this binuclear zinc compound leads to isolation of the C‐alkylated product in 89 % yield. A reaction pathway is proposed in which BM(diPh)IK initially coordinates to diethylzinc as a bidentate bis(nitrogen) ligand. This is followed by the homolytic cleavage of the Zn–Et bond and in‐cage recombination of the Et‐radical and the Zn‐coordinated ligand‐centered radical, which is mainly localized on the carbonyl moiety of the ligand.