Isolation and Characterization of a Chiral η1-Allyl Palladium DIPPAM Complex: Application to the Enantioselective Pd-Catalyzed Allylic Alkylation

Abstract

In the presence of [Cl(C3H5)Pd]2, diphenylphosphinoazomethinylate salt (DIPPAM) 1a forms an original chiral η1-allyl palladium complex, 2. Precatalyst 2/MgBr2 is an efficient catalyst for asymmetric allylic alkylation, giving good yields and ee’s in the reactions of rac-4-acetoxy-2-pentene or rac-3-acetoxy-1,3-diphenyl-1-propene and dimethyl malonate (respectively 77% and 96% yield; 66% and 96% ee). Preliminary mechanistic studies have highlighted the key role of the η1-coordination mode of the allyl fragment.