Practical Syntheses of Chiral α-Amino Acids and Chiral Half-Esters by Kinetic Resolution of Urethane-Protected α-Amino Acid <i>N</i>-Carboxyanhydrides and Desymmetrization of Cyclic <i>meso</i>-Anhydrides with New Modified Cinchona Alkaloid Catalysts
作者:Yutaka Ishii、Ryosuke Fujimoto、Masafumi Mikami、Satoshi Murakami、Yasushi Miki、Yoshiro Furukawa
DOI:10.1021/op700023h
日期:2007.5.1
The large-scale applications of the kinetic resolution of urethane-protected α-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 α-amino acids 6 and chiral half-esters 2 on an industrial scale, because the organocatalyst
描述了氨基甲酸酯保护的α-氨基酸N-羧基酐(UNCA)的动力学拆分的大规模应用和使用改性金鸡纳生物碱对环状内消旋酸酐的脱对称化。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,而无需色谱纯化步骤。改性金鸡纳生物碱催化剂(DHQD)2 AQN和(DHQ)2正如邓和同事所报道的,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。这些新的催化剂施加到的手性炔丙基甘氨酸的合成24和BAY10-8888 / PLD-118,关键中间体26,在工业规模上,通过UNCA的动力学拆分22和环状的desymmetrization内消旋-酸酐25。