Enantioselective synthesis of beta-amino acids using hexahydrobenzoxazolidinones as chiral auxiliaries
作者:Gloria Reyes-Rangel、Erika Jiménez-González、José Luis Olivares-Romero、Eusebio Juaristi
DOI:10.1016/j.tetasy.2008.12.023
日期:2008.12
A practical synthetic route for the asymmetric synthesis of β2-amino acids is described. In the first step, the procedure involves the N-acylation of readily available, enantiopure hexahydrobenzoxazolidinone (4R,5R)-1 with 3-methylbutanoyl chloride 2, 4-methylpentanoic acid 3, and 3-(1-tert-butoxycarbonyl)-1H-indol-3-yl)propanoic acid 4 to afford derivatives 5a, 5b, and 5c, respectively, which were
对于β的不对称合成的实用合成路线2种α-氨基酸进行说明。在第一步骤中,所述程序包括容易得到的,对映体纯hexahydrobenzoxazolidinone(4的N-酰化- [R,5 - [R )- 1用3-甲基丁酰氯2,4-甲基戊酸3,和3-(1-叔丁氧羰基) -1 H-吲哚-3-基)丙酸4得到衍生物5a,5b和5c分别通过它们的烯醇钠和溴乙酸苄酯之间的反应以高非对映选择性将其烷基化。的手性从烷基化产物辅助去除,随后氢化和水解,得到β 2 α-氨基酸(小号) - 10A,(小号) - 10B,和(小号) - 10C,这是Ñ -保护用Fmoc。对映异构体(R)-10a – c同样由异构体六氢苯并恶唑烷酮(4 S,5 S)-1制备。; 因此,路线呈现这里提供了访问的有价值的对映体富集的高度β两种对映体2 α-氨基酸。