Enantioselective Construction of Quaternary α-Carbon Centers on α-Amino Phosphonates via Catalytic Asymmetric Allylation

Abstract

Asymmetric allylation of α-acetamido β-keto phosphonates was promoted, in the presence of potassium tert-butoxide as a base, by a palladium catalyst prepared from [Pd(π-allyl)(cod)]BF4 and (R)-BINAP and gave the corresponding α-alkyl α-amino phosphonic acid derivatives with 65−88% ee. Diastereoselective reduction of the carbonyl group in the product was accomplished by NaBH4 or Bu4NBH4. The diastereoselection in the reduction was reversed by choice of solvent.