Enantioselective Synthesis of Diamino Dicarboxylic Acids HieblJohann KollmannHermann RovenszkyFranz WinklerKarin 1999 The preparation of alkyl diamino dicarboxylic acids with high optical purity (100% ee, >98.5% de) and high yields based on asymmetric catalytic hydrogenation is described. The required prochiral precursors are prepared from dialdehydes and Z-, Boc-, and acetyl-protected phosphonoglycines. Aqueous solutions 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-Protected dimethyl esters of DAA, DAS, and DAZ were obtained by hydrogenation of the corresponding prochiral starting materials with [(COD)Rh(<i>S</i>,<i>S</i>)-Et-DuPHOS]OTf.