Biimidazoline Ligands For Palladium-Catalyzed Asymmetric Allylic Alkylation

In this thesis, the application of biimidazolines in asymmetric allylic alkylation was evaluated. The main results are as follows:According to the synthetic method of our group, a series of biimidazolines 3 were prepared by means of a one-pot route consisting of six steps which began with chiral amino acids(Scheme 1). The catalytic efficiency of biimidazolines in palladium-catalyzed asymmetric allylic alkylation using rac-1,3-diphenyl-2-propenyl acetate 4(R3 = R3’ = Ph) and dimethyl malonate 5(R4 = Me) as model substrates was explored. Under the optimized reaction conditions including the employment of a mixture of 2.25 mol% [Pd(η3-C3H5)Cl]2 and 4.5 mol% ligand 3d(R1 = t-Bu, R2 = oCH3O-C6H4) as the catalyst, Cs2CO3(0.2 equiv.) as the base, and BSA(3.0 equiv.) as the additive in CH2Cl2 at 35 °C for 5 h, the desired products 6 were obtained in up to 99% yield and 97% ee(Scheme 2).