Metal-promoted allylation, propargylation, or allenylation of azetidine-2,3-diones in aqueous and anhydrous media. Application to the asymmetric synthesis of densely functionalized 3-substituted 3-hydroxy-beta-lactams

Metal-mediated carbonyl allylation, allenylation, and propargylation of opt ically pure azetidine-2,3-diones were investigated in both anhydrous and aq ueous environments. Different metals promoters showed varied regioselectivi ties on product formation during allenylation/propargylation reactions of t he keto-beta -lactams. The stereochemistry of the new C3-substituted C3-hyd roxy quaternary center was controlled by placing a chiral auxiliary at C4. In this way, the coupling of azetidine-2,3-diones with a variety of propeny l-, propynyl-, and allenylmetal reagents offers a convenient asymmetric ent ry to potentially bioactive 3-substituted 3-hydroxy-beta -lactams.