(S)-alpha-methyl,alpha-amino acids: a new stereocontrolled synthesis.
A new and convenient stereocontrolled synthesis of the optically pure (S)-alpha-methyl,alpha-amino acids 6(a-d) that exploits the chiral synthon 1,4-N,N-[(S)-1-phenylethyl]-piperazine-2,5-dione (1) is described. The (S)-1-phenylethyl group, bonded to each of the N-atoms of the 2,5-diketopiperazine, acts as a chiral inductor in the first alkylation, while the steric hindrance appears to be the determining factor of stereocontrol in third and forth alkylation.
Balducci
Daniele
D
Dipartimento di Chimica G.Ciamician, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy. daniele.balducci4@unibo.it
Lazzari
Ilaria
I
Monari
Magda
M
Piccinelli
Fabio
F
Porzi
Gianni
G
D000409:Alanine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D000613:Aminobutyrates / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D054659:Diketopiperazines / Q000138:chemical synthesis / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D013237:Stereoisomerism; D014633:Valine / Q000138:chemical synthesis / Q000737:chemistry
C550458:1,4-N,N-(phenylethyl)piperazine-2,5-dione; D000596:Amino Acids; D000613:Aminobutyrates; D054659:Diketopiperazines; C032737:isovaline; C014328:2-amino-4-phenylbutyric acid; D014633:Valine; D000409:Alanine