Development of a New Class of Chiral Phosphorus Ligands: P-Chirogenic Diaminophosphine Oxides. A Unique Source of Enantioselection in Pd-Catalyzed Asymmetric Construction of Quaternary Carbons
phosphorus compounds have been successfully applied to Pd-catalyzed asymmetric construction of tertiary and quaternary carbons. The actual ligand structure was the trivalent phosphorus species 17, which was generated in situ by BSA-induced P(V) to P(III) transformation of 6, the preligand. Detailed mechanistic studies, including asymmetric amplification and initial rate kinetics, revealed that complex 18
Enantioselective Construction of All-Carbon Quaternary Stereocenters Using Palladium-Catalyzed Asymmetric Allylic Alkylation of γ-Acetoxy-α,β-unsaturated Carbonyl Compounds
β-unsaturated carbonyl compounds are useful starting materials for Pd-catalyzed asymmetricallylicalkylation to construct all-carbon quaternary stereocenters. With the use of 2–5 mol % of Pd catalyst and 4–10 mol % of P-chirogenic diaminophosphine oxides, asymmetricallylicalkylation of γ-acetoxy-α,β-unsaturated carbonyl compounds with various prochiral nucleophiles derived from cyclic β-keto esters proceeded