Unusual amino acids VI. Substituted arylamino acids by asymmetric hydrogenation of N-Cbz and N-Boc protected dehydroamino acid derivatives |
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Authors: | H. W. Krause,H.-J. Kreuzfeld,U. Schmidt,CH Dö bler,M. Michalik,S. Taudien,Ch. Fischer |
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Abstract: | Substituted N-Cbz and N-Boc protected arylamino acrylic acids and esters have been prepared and used in asymmetric hydrogenations catalyzed by PROPRAPHOSRh. Stereoselectivities > 90% ee could be achieved, the rate of which is dependent on the position of the substituent in the aromatic ring. The N-Boc derivatives provide advantages compared with the N-Cbz analogues. The amino acid derivatives were fully characterized by 19F, 13C, and 1H NMR spectroscopy. © 1996 Wiley-Liss, Inc. |
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Keywords: | amino acids chiral rhodium complexes aminophosphine-phosphinite D- and L-enantiomers NMR spectra |
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