Unusual amino acids VI. Substituted arylamino acids by asymmetric hydrogenation of N-Cbz and N-Boc protected dehydroamino acid derivatives

✍ Scribed by H. W. Krause; H.-J. Kreuzfeld; U. Schmidt; CH Döbler; M. Michalik; S. Taudien; Ch. Fischer

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 997 KB
• Volume: 8
• Category: Article
• ISSN: 0899-0042
• DOI: 10.1002/(sici)1520-636x(1996)8:2<173::aid-chir2>3.0.co;2-k

✦ Synopsis

Substituted N-Cbz and N-Boc protected arylamino acrylic acids and esters have been prepared and used in asymmetric hydrogenations catalyzed by PROPRAPHOS-Rh. 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 "F, 13C, and ' H NMR spectroscopy.