Lewis Acid-Promoted 1,4-Addition to Chiral Imide Derivatives in the Synthesis of β-Amino Acids

Article abstract of DOI:10.1021/jo00073a017

The 1,4-addition of O-benzylhydroxylamine to imides 3 in the presence of various Lewis acids is described.The reaction is performed in CH2Cl2 at -78 deg C and affords derivatives 4 and 5 in good chemical yields and in different diastereomeric ratios, depending on the Lewis acid employed.TiCl4 and Me2AlCl give opposite diastereoselectivities.Furthemore, enantiomerically pure β-amino acid 9 is obtained in good yield from compound 4a.