A new method for the asymmetricsynthesis of threo and erythro β-phenylserines using (+)-ketopinic acid as a chiral auxiliary is reported. The reaction was based on the condensation of benzaldehyde with the metal (Li+, K+ or Zn++, enolates of the chiral imines .
Rhodium-catalyzed asymmetric hydrogenation through dynamic kinetic resolution: asymmetric synthesis of anti-β-hydroxy-α-amino acid esters
作者:Kazuishi Makino、Takefumi Fujii、Yasumasa Hamada
DOI:10.1016/j.tetasy.2006.01.040
日期:2006.2
Rhodium-catalyzed asymmetrichydrogenation of α-amino-β-keto ester hydrochlorides through dynamic kineticresolution is described. The hydrogenation proceeds with the catalyst derived from a Rh complex and a chiral ferrocenylphosphine under hydrogen in the presence of sodium acetate in acetic acid to afford anti-β-hydroxy-α-amino acid esters with 58–83% ee in a diastereomeric ratio of 92:8–97:3.
syn α-benzoylamido β-hydroxy esters through asymmetrictransferhydrogenation (ATH) with a tethered Rh(III)–DPEN complex via dynamic kinetic resolution (DKR) has been developed for the first time starting from α-benzoylamido β-keto esters. A variety of α-benzoylamido β-keto esters were converted under mild conditions into the corresponding syn α-benzoylamino β-hydroxy esters with high yields (up to 98%)