Asymmetric strecker synthesis of alpha-amino acids via a crystallization-induced asymmetric transformation using (R)-phenylglycine amide as chiral auxiliary.
[reaction: see text]. Diastereoselective Strecker reactions based on (R)-phenylglycine amide as chiral auxiliary are reported. The Strecker reaction is accompanied by an in situ crystallization-induced asymmetric transformation, whereby one diastereomer selectively precipitates and can be isolated in 76-93% yield and dr > 99/1. The diastereomerically pure alpha-amino nitrile obtained from pivaldehyde (R1 = t-Bu, R2 = H) was converted in three steps to (S)-tert-leucine in 73% yield and >98% ee.
Boesten
W H
WH
DSM Research Life Sciences-Organic Chemistry and Biocatalysis, P.O. Box 18, 6160 MD Geleen, and Syncom B.V., Kadijk 3, 9747 AT Groningen, The Netherlands.
Seerden
J P
JP
de Lange
B
B
Dielemans
H J
HJ
Elsenberg
H L
HL
Kaptein
B
B
Moody
H M
HM
Kellogg
R M
RM
Broxterman
Q B
QB
D000577:Amides / Q000737:chemistry*; D000596:Amino Acids / Q000138:chemical synthesis*; D003460:Crystallization; D018360:Crystallography, X-Ray; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D013237:Stereoisomerism; D013696:Temperature
D000577:Amides; D000596:Amino Acids; C021316:N-phenylglycine; D005998:Glycine