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首页> 外文期刊>Organic process research & development >Practical syntheses of chiral alpha-amino acids and chiral half-esters by kinetic resolution of urethane-protected alpha-amino acid N-carboxyanhydrides and desymmetrization of cyclic meso-anhydrides with new modified cinchona alkaloid catalysts
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Practical syntheses of chiral alpha-amino acids and chiral half-esters by kinetic resolution of urethane-protected alpha-amino acid N-carboxyanhydrides and desymmetrization of cyclic meso-anhydrides with new modified cinchona alkaloid catalysts

机译：通过氨基甲酸酯保护的α-氨基酸N-羧基酐的动力学拆分和环状介孔酸酐的不对称化与新型改性金鸡纳生物碱催化剂的实用合成手性α-氨基酸和手性半酯

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摘要

The large-scale applications of the kinetic resolution of urethane-protected r- amino acid N-carboxyanhydrides (UNCAs) and the desymmetrization of cyclic meso-anhydrides using modified cinchona alkaloids are described. These asymmetric reactions are effective organocatalytic methods for the synthesis of chiral alpha-amino acids 6 and chiral half-esters 2 on an industrial scale, because the organocatalyst recovery and product purification can be carried out by a simple extractive procedure obviating a chromatographic purification step. The modified cinchona alkaloid catalysts (DHQD)(2)AQN and (DHQ)(2)AQN, as reported by Deng and co-workers, are not readily available and therefore not suitable for industrial-scale synthesis. Various O-alkylated quinidine and quinine derivatives were prepared and screened as catalysts for the kinetic resolution of phenylalanine UNCA with alcohol. The readily prepared O-propargylquinidine (OPQD) and O-propargylquinine (OPQ) were discovered to be highly enantioselective and practical catalysts. These new catalysts were applied to the synthesis of chiral propargylglycine 24 and the key intermediate of BAY10-8888/PLD-118, 26, on an industrial scale, by the kinetic resolution of UNCA 22 and the desymmetrization of cyclic meso-anhydride 25, respectively.
机译：描述了氨基甲酸酯保护的r-氨基酸N-羧基酸酐（UNCA）的动力学拆分的大规模应用以及使用修饰的金鸡纳生物碱对环状内消旋酸酐的脱对称性。这些不对称反应是在工业规模上合成手性α-氨基酸6和手性半酯2的有效有机催化方法，因为有机催化剂的回收和产物纯化可以通过简单的萃取程序进行，而无需进行色谱纯化步骤。邓和同事报告的改性金鸡纳生物碱催化剂（DHQD）（2）AQN和（DHQ）（2）AQN尚不容易获得，因此不适合工业规模的合成。制备了各种O-烷基化的奎尼丁和奎宁衍生物，并筛选了用醇动力学拆分苯丙氨酸UNCA的催化剂。发现容易制备的O-炔丙基奎尼丁（OPQD）和O-炔丙基奎尼丁（OPQ）是高度对映选择性和实用的催化剂。这些新催化剂分别通过UNCA 22的动力学拆分和环状内消旋酸酐25的去对称化，在工业规模上用于手性炔丙基甘氨酸24和BAY10-8888 / PLD-118 26的关键中间体的合成。 。

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