A series of magnesium inner complexes has been prepared by reacting MgH2 (prepared by homogeneous catalysis) with dialkylallyl- and -3-butenylamines and -3-butenylethers in the presence of catalytic amounts of ZrCl4. The monomeric nature of bis(4-methoxybutyl)magnesium has been confirmed by X-ray diffraction.The analogous syntheses of bis(3-alkoxypropyl)magnesium compounds failed: cleavage of the allyl ether with elimination of propene occurred. This cleavage reaction is accelerated by catalytic amounts of NiCl2 or ZrCl4

Abstract The reaction of bis(dialkylaminoalkyl)-and bis(4-alkoxybutyl)magnesium inner complexes with MgEt2 leads to the formation of ethyl(dialkylaminoalkyl)-and ethyl(4-alkoxybutyl)magnesium compounds. The X-ray crystal structures of ethyl(3-N,N-dimethylam inopropyl)magnesium and ethyl(3-N-cyclohexyl-3-N-methylaminopropyl)magnesium confirm that the com pounds are dimeric with the α-C-atom of the chelating ligand bridging the magnesium atoms.The difference in reactivity of the Mg-Et and Mg-CnH2nX bonds (X = NR′R″, OR) makes itself apparent in the reaction of these complexes with ethylene: up to six ethylene molecules are inserted, whereby in the case of the ethyl(4-alkoxybutyl)magnesium compounds insertion occurs preferentially into the Mg-Et bond whereas in the case o f the ethyl(dialkylaminoalkyl)magnesium compounds both bonds are equally reactive.

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