[(CH2CH)2Al(μ-OCH2CH2NMe2)]2: a vinylalane reagent suitable for conjugate additions to α,β-unsaturated ketones

The reaction of AlCl3 with 2-dimethylaminoethanol in a 1:1 mole ratio yields [Cl2Al(μ-OCH2CH2NMe2)]2 (1), which further reacts with two equivalents of vinylmagnesium chloride to give the divinylalane [(CH2CH)2Al(μ-OCH2CH2NMe2)]2 (2). Compound 2 was characterized by elemental analysis, 1H, 13C, and 27Al NMR spectra, mass spectrum and by X-ray structural analysis. Compound 2 was found to be a useful reagent for the transfer of a vinyl group to 1,3-diphenyl-2-propene-1-one (trans-chalcone). The 1,4-addition product is formed regioselectively, both in a non-catalyzed as well as in a nickel-catalyzed reaction.