Synthesis of C-protected alpha-amino aldehydes of high enantiomeric excess from highly epimerizable N-protected alpha-amino aldehydes.
A new procedure for the preparation of C-protected alpha-amino aldehydes of high enantiomeric excess is illustrated using five differently substituted alpha-(N-Fmoc)amino aldehydes as starting materials. Highly epimerization-prone substrates were converted to the corresponding morpholino nitrile-protected alpha-amino aldehydes with minimal racemization (products >/= 89% ee). Morpholino nitrile derivatives of phenylglycinal were crystallized and subjected to X-ray structural analysis, allowing for definitive determination of the stereochemistry of amino nitrile formation. A rationale for the stereoselectivity of amino nitrile formation is presented.
Myers
A G
AG
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA. myers@chemistry.harvard.edu
Zhong
B
B
Kung
D W
DW
Movassaghi
M
M
Lanman
B A
BA
Kwon
S
S
D000447:Aldehydes / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism; D014961:X-Ray Diffraction
D000447:Aldehydes