Efficient asymmetric synthesis of α-amino acids through hydrogenation of α,β-dehydroamino acid residue in cyclic dipeptides

✍ Scribed by Tatsuhiko Kanmera; Sannamu Lee; Haruhiko Aoyagi; Nobuo Izumiya

• Publisher: Elsevier Science
• Year: 1979
• Tongue: French
• Weight: 290 KB
• Volume: 20
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)86625-9

✦ Synopsis

A series of cycZo(Aaminoacyl-L-Ala) (fl) (A=a,@dehydro) were prepared from cycZo(Gly-L-Ala) and corresponding aldehyde, and hydrogenated with Pd black in MeOH. Chiral inductions producing CycZo(L-aminoacyl-L-Ala) (2) from 2 were 96-99% in the case of L-Aba (2-eminobutanoic acid), L-Val, L-Leu, and L-App (2-amino-5-phenylpentanoic acid) as an L-aminoacyl moiety in 5. -Pure L-Leu, L-Aba, and L-App were synthesized in preparative scale from corresponding 4 through asymmetric hydrogenation and acid-hydrolysis.

We reported high asymmetric hydrogenation of hAla (A=a,B-dehydro) residue in CyOZO(hAla-L-~eu) and preparation of pure L-alanine through acid-hydrolysis of cycZo(L-Ala-L-Leu) obtained.

1,2

The key intermediate, cycZo(AAla-L-Leu), was synthesized from cycZo(L-Ser-L-Leu) by Photaki's method, 3 namely tosylation of Ser residue and successive detosylation by the action of Et2NH.