Diastereo- and Enantioselective Synthesis of 2-Substituted 1-Aminocyclopropane-1-Carboxylic Acids. Application to the Synthesis of Protected 2,3-Methano Analogs of Ornithine and Glutamic Acid
作者:Jeffrey A. Frick、John B. Klassen、Henry Rapoport
DOI:10.1055/s-2005-870007
日期:——
An enantiodivergent synthesis of protected 2,3-methano amino acid analogs is described. (R)-2-benzyloxyethyloxirane, prepared from (S)-aspartic acid, was reacted with tert-butyl hydrogen malonate and further transformed into an enantiomeric pair of intermediate cyclopropane-fused-lactones, 1-carboxy-2-oxo-3-oxabicyclo[4.1.0]heptane. Each of these enantiomers allowed differentiation of the carboxy functions and generation of a 2-hydroxyethyl group on the cyclopropanes, thus affording access to any or all four stereoisomers. The two-carbon pendant allowed for the direct synthesis of protected 2,3-methano analogs of glutamic acid and ornithine and can be used for other useful transformations.
本文描述了一种受保护的 2,3-甲桥氨基酸类似物的对映异构合成方法。由(S)-天冬氨酸制备的(R)-2-苄氧基乙基环氧乙烷与丙二酸叔丁酯反应,并进一步转化为一对对映体的中间环丙烷融合内酯--1-羧基-2-氧代-3-氧杂双环[4.1.0]庚烷。这些对映体中的每一种对映体都可以区分羧基功能,并在环丙烷上生成一个 2-羟乙基,从而获得任何或所有四种立体异构体。这种双碳垂体可以直接合成谷氨酸和鸟氨酸的受保护 2,3-甲烷类似物,并可用于其他有用的转化。