A New Method for the Synthesis of β-Amino Acid Derivatives and β-Lactams. Reaction of N-Alkoxycarbonyl-1-methoxyamines with Esters

The reaction of N -alkoxycarbonyl-1-methoxyamines with esters is an alternative to the reaction of imines with esters for the synthesis of β-amino acid derivatives. In this reaction, N -alkoxycarbonyl-1-methoxyamines corresponding to unstable imines can also be employed. Although anti adducts were obtained preferentially in the absence of Ti complexes, the diastereoselectivity of this reaction was reversed by the addition of Ti(OPr- i ) 4 . The obtained adducts were transformed to the corresponding β-lactams.