Synthesis and properties of the eight isostatine stereoisomers
摘要:
The eight possible stereoisomers of isostatine, (3S,4R,5S)-4-amino-3-hydroxy-5-methylheptanoic acid, have been synthesized from the four isomeric D- and L-isoleucinals and D- and L-allo-isoleucinals and ethyl lithioacetate. The eight isomers have been compared for the GC retention times of their bis(trifluoroacetyl) methyl ester derivatives and the H-1 NMR properties of the gamma-lactams derived from them. The natural isomer was shown to be the 3S,4R,5S isomer.
Stereo- and regio-selective one-pot synthesis of triazole-based unnatural amino acids and β-amino triazoles
作者:R. B. Nasir Baig、Rajender S. Varma
DOI:10.1039/c2cc32392c
日期:——
Synthesis of triazole based unnatural amino acids and β-amino triazoles has been described via a stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW conditions. The developed method is applicable to a broad substrate scope and has significant potential for the synthesis of unnatural amino acids with a triazole side chain.
Samarium Iodide-Mediated Reformatsky Reactions for the Stereoselective Preparation of β-Hydroxy-γ-amino Acids: Synthesis of Isostatine and Dolaisoleucine
作者:Christopher G. Nelson、Terrence R. Burke
DOI:10.1021/jo202091r
日期:2012.1.6
The synthesis of β-hydroxy-γ-amino acids via SmI2-mediated Reformatskyreactions of α-chloroacetyloxazolidinones with aminoaldehydes is reported. Diastereoselective coupling is demonstrated to depend on the absolute configuration of the Evans chiral auxiliary employed in the reaction, allowing erythro or threo products to be obtained selectively. The potential utility of the methodology is exemplified