Diastereoselective synthesis of quaternary alpha-amino acids from diketopiperazine templates.
Sequential enolate alkylations of (S)-N(1)-methyl-5-methoxy-6-isopropyl-3,6-dihydropyrazin-2-one and (S)-N(1)-p-methoxybenzyl-5-methoxy-6-isopropyl-3,6-dihydropyrazin-2-one proceed with excellent levels of diastereoselectivity (>90% de) affording quaternary alpha-amino acids in high enantiomeric excess (>98% ee) after deprotection and hydrolysis.
Davies
Stephen G
SG
Department of Organic Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK. steve.davies@chem.ox.ac.uk
Garner
A Christopher
AC
Ouzman
Jaqueline V A
JV
Roberts
Paul M
PM
Smith
Andrew D
AD
Snow
Emma J
EJ
Thomson
James E
JE
Tamayo
Juan A
JA
Vickers
Richard J
RJ
D000478:Alkylation; D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D054659:Diketopiperazines; D006868:Hydrolysis; D007769:Lactams / Q000737:chemistry; D008745:Methylation; D008958:Models, Molecular; D015394:Molecular Structure; D010879:Piperazines / Q000737:chemistry*; D011522:Protons; D013237:Stereoisomerism
D000596:Amino Acids; D054659:Diketopiperazines; D007769:Lactams; D010879:Piperazines; D011522:Protons