Enantioselective synthesis of 2-substituted 3-aminopropanoic acid (β-alanine) derivatives which are β-analogues of aromatic amino acids
作者:Elena Arvanitis、Holger Ernst、Alice A. LudwigéD’Souza、Andrew J. Robinson、Peter B. Wyatt
DOI:10.1039/a706163c
日期:——
3-Aminopropanoic acid derivatives with a phenyl, 4-hydroxyphenyl, benzyl or indol-3-yl substituent at C-2 can be prepared enantioselectively by routes involving electrophilic attack of synthetic equivalents of [H2NCH2]+ upon enolates derived from chiral 3-acyl-1,3-oxazolidin-2-ones. tert-Butyl bromoacetate may be used as the electrophile, with subsequent introduction of nitrogen through the Curtius reaction, using the sequence of reagents (i) CF3CO2H; (ii) (PhO)2P(O)N3, Et3N, PhCH2OH; alternatively, direct electrophilic reaction with 1-[N-(benzyloxycarbonyl)aminomethyl]benzotriazole 4c or benzyl N-(acetoxymethyl)carbamate 2d introduces a protected aminomethyl group in a single step.
具有苯基、4-羟基苯基、苄基或吲哚-3-基的C-2取代基的3-氨基丙酸衍生物可以通过涉及合成[H2NCH2]+的亲电攻击的路线,从手性3-酰基-1,3-恶唑烷-2-酮衍生的烯醇盐选择性地制备。可以使用叔丁基溴乙酸酯作为亲电试剂,随后通过Curtius反应引入氮,使用试剂序列(i)CF3CO2H;(ii)(PhO)2P(O)N3,Et3N,PhCH2OH;或者,直接与1-[N-(苄氧羰基)氨基甲基]苯并三唑4c或苄基N-(乙酸甲酯)氨基甲酸酯2d进行亲电反应,一步引入保护的氨基甲基基团。