Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Novel and effective routes to optically pure aromatic α-amino acids, α-methyl-α-amino acids and their derivatives including dipeptides are developed via homochiral β-lactams which are obtained through asymmetric [2+2] cycloadditions of ketenes to imines. ... RC Pandey, H. Meng, ...