Tetrahedron: Asymmetry

Application of the asymmetric hydrogenation of enamines to the preparation of a beta-amino acid pharmacophore

M Kubryk, KB Hansen

文献索引：Kubryk, Michele; Hansen, Karl B. Tetrahedron Asymmetry, 2006 , vol. 17, # 2 p. 205 - 209

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被引用次数: 54

摘要

(3R)-3-[N-(tert-Butoxycarbonyl) amino]-4-(2, 4, 5-trifluorophenyl) butanoic acid 7a has been synthesized by an asymmetric hydrogenation of enamine ester 3 using chiral ferrocenyl ligands I and II in conjunction with [Rh (COD) Cl] 2. The direct reduction of 3 provides amino ester 1b in 93% ee, which was isolated as an (S)-camphorsulfonic acid salt to upgrade the enantiomeric excess to> 99%. A more concise approach was developed involving the in ...