Chiral tricyclic iminolactone derived from (1R)-(+)-camphor as a glycine equivalent for the asymmetric synthesis of alpha-amino acids.
The development of a highly efficient and stereoselective methodology for the preparation of alpha-amino acids is described. The chiral template, tricyclic iminolactone 7, was synthesized from (1R)-(+)-camphor in five steps in 50% overall yield. Alkylation of iminolactone 7 afforded the alpha-monosubstituted products in good yields (74-96%) and excellent diastereoselectivities (>98%). Hydrolysis of the alkylated iminolactones furnished the desired alpha-amino acids in good yields and enantioselectivities with nearly quantitative recovery of the chiral auxiliary 4.
Xu
Peng-Fei
PF
College of Chemistry and Chemical Engineering, National Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000, PRC.
Chen
Yuan-Shek
YS
Lin
Shu-I
SI
Lu
Ta-Jung
TJ
D000409:Alanine / Q000737:chemistry; D000478:Alkylation; D000596:Amino Acids / Q000138:chemical synthesis*; D002164:Camphor / Q000737:chemistry; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D018360:Crystallography, X-Ray; D003500:Cyclization; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry; D006868:Hydrolysis; D007783:Lactones / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D010649:Phenylalanine / Q000737:chemistry; D013237:Stereoisomerism
D000596:Amino Acids; D007783:Lactones; D010649:Phenylalanine; D002164:Camphor; D000409:Alanine; D005998:Glycine