Reactions between some organozinc compounds and 2-dimethylaminoethanol, acetoxime, phenylisocyanate, and benzophenone. Some observations on the methylzinc methoxide tetramer

Abstract

Zinc alkyls and 2-dimethylaminoethanol eliminate hydrocarbon giving trimers (RZnO·C₂H₄·NMe₂)₃(R = Me, Et). The tetrameric products, e.g., (MeZnON:CMe₂)₄ and (EtZnNPhCOEt)₄, from zinc alkyls and acetoxime and phenyl isocyanate are formulated with parallel six- and eight-membered rings, respectively, the interaction between the rings arising from the tendency of the metal to be four rather than three co-ordinate.

The near-cubic structure of the crystalline methylzinc methoxide tetramer persists in cyclohexane solution and interaction with pyridine is slight. · The tetramer yields an adduct with 4-dimethylaminopyridine which dissociates extensively in solution to tetramer and free base.

Diethylzinc eliminates ethylene quantitatively in reaction with benzophenone, giving the trimer (EtZnOCHPh₂)₃. Diphenylzinc adds to the carbonyl group forming a dimer, (PhZnOCPh₃)₂.