The synthesis of (2S, 3S)-and (2S, 3R)-2, 3-diamino-4-phenylbutanoic acid (IC and 3) from L- aspartic acid is described. The N-(phenylfluorenyl)-prote&d aspartic acid diesters 4 and 10 (a-tert-butyl,@-methyl), 18@-benzyl, a-tert-butyl), and 28 (@-benzyl, a-methyl) are regioselectively benzylated at C-3 by using KHMDS and benzyl bromide or iodide. Whereas the alkylation of compounds 4 and 28 proceeds in low to moderate diastereoselectivities, ...
