Enantioselective synthesis of diamino dicarboxylic acids

The preparation of alkyl diamino dicarboxylic acids with high optical purit y (100% ee, >98.5% de) and high yields based on asymmetric catalytic hydrog enation is described. The required prochiral precursors are prepared from d ialdehydes and Z-, Boc-, and acetyl-protected phosphonoglycines. Aqueous so lutions of glyoxal, succinic dialdehyde, and glutaric dialdehyde were used to prepare the diunsaturated precursors for 2,5-diaminoadipic acid (DAA), 2 ,7-diaminosuberic acid (DAS), and 2,8-diaminoazelaic acid (DAZ). Z-Protecte d dimethyl esters of DAA, DAS, and DAZ were obtained by hydrogenation of th e corresponding prochiral starting materials with [(COD)Rh(S,S)-Et-DuPHOS]O Tf.