Synthesis of Enantiopure (S)-Indolylglycine by Organocatalyzed Friedel–Crafts Alkylation of Indole
作者:Martin J. Wanner、Peter Hauwert、Hans E. Schoemaker、René de Gelder、Jan H. van Maarseveen、Henk Hiemstra
DOI:10.1002/ejoc.200700886
日期:2008.1
Tritylsulfenyl- and 2-nitrophenylsulfenyl-substituted glyoxyl imines were used in chiral phosphoric acid catalyzed Friedel-Crafts (FC) reactions with indole. High yields and ee values ranging from 86% for Nps-protected (S)-indolylglycine to 88% for Trs-protected (R)-indolylglycine were obtained. On a preparative scale, a FC product with 99.5% ee and 71% yield was readily obtained by crystallization
Tritylsulfenyl-和2-nitrophenylsulfenyl-取代的乙醛亚胺用于手性磷酸催化的与吲哚的Friedel-Crafts (FC)反应。获得了高产率和 ee 值,范围从 Nps 保护的 (S)-吲哚甘氨酸的 86% 到 Trs 保护的 (R)-吲哚甘氨酸的 88%。在制备规模上,通过反应混合物的结晶很容易获得具有 99.5% ee 和 71% 产率的 FC 产品。在温和的酸性条件下去除 Nps 保护基不会影响 α-碳原子的立体化学完整性,并且以 >= 98% ee 提供 (S)-吲哚甘氨酸。
Concise Preparation of Optically Active Heteroaryl α-(Hydroxyamino) Esters
for the synthesis of optically active heteroaryl α-(hydroxyamino) esters was explored. The highly diastereoselective addition of heteroaromatics to a cyclic chiral nitrone allowed access to a series of heteroaryl hydroxylamines. The scope of this reaction was evaluated on substrates possessing a pyrrole, an indole, or a furan core. The three-step sequence afforded the α-(hydroxyamino) esters in good