Efficient Synthesis of Enantiomerically Pure β<sup>2</sup>-Amino Acids via Chiral Isoxazolidinones
作者:Hee-Seung Lee、Jin-Seong Park、Byeong Moon Kim、Samuel H. Gellman
DOI:10.1021/jo026738b
日期:2003.2.1
We report a practical and scalable synthetic route for the preparation of alpha-substituted beta-amino acids (beta(2)-amino acids). Michael addition of a chiral hydroxylamine, derived from alpha-methylbenzylamine, to an alpha-alkylacrylate followed by cyclization gives a diastereomeric mixture of alpha-substituted isoxazolidinones. These diastereomers are separable by column chromatography. Subsequent
我们报告了一种实用且可扩展的合成路线,用于制备α-取代的β-氨基酸(β(2)-氨基酸)。将衍生自α-甲基苄基胺的手性羟胺迈克尔加成至α-烷基丙烯酸酯,然后环化,得到α-取代的异恶唑烷酮的非对映异构体混合物。这些非对映异构体可通过柱色谱法分离。纯化的异恶唑烷酮的随后氢化,然后进行Fmoc保护,得到对映体纯的Fmoc-β(2)-氨基酸,可用于合成β-肽。该途径提供了获得保护的β(2)-氨基酸的两种对映异构体的途径。