A library of chiral imidazoline-aminophenol ligands: Discovery of an efficient reaction sphere

被引：103

作者：

Arai, Takayoshi ^{[1
]}

Yokoyama, Naota ^{[1
]}

Yanagisawa, Akira ^{[1
]}

机构：

[1] Chiba Univ, Grad Sch Sci, Dept Chem, Chiba 2638522, Japan

来源：

CHEMISTRY-A EUROPEAN JOURNAL | 2008年 / 14卷 / 07期

关键词：

asymmetric catalysis; circular dichroism; combinatorial chemistry; high-throughput screening; solid-phase synthesis;

D O I：

10.1002/chem.200701439

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

A library of imidazoline-aminophenol ligands was synthesized on solid supports. After immobilization of chiral chloromethylimidazolines 1 and 2 onto the polystyrylsulfonyl chloride, nucleophilic substitution with (R)or (S)-phenylethylamine (3 and 4) provided four combinations of polymer-supported imidazoline-amine ligands. Further reductive alkylation using salicylaldehydes 7-10 provided a series of imidazoline-aminophenol ligands (L9-L24). Analysis by solid-phase catalysis/circular dichroism high-throughput screening of a copper-catalyzed Henry reaction revealed that ligand L25, comprising a (S,S)-diphenylethylenediamine-derived imidazoline, (S)-phenyle-thylamine, and dibromophenol, was highly efficient, thus providing the adduct of nitromethane and benzaldehyde in 95% ee. The combination of stereogenic centers was crucial in promoting the highly stereoselective reactions. The unique reaction sphere of L25 was also examined in a FriedelCrafts alkylation of indole and nitroalkene to give the adduct in up to 83% ee.

引用

页码：2052 / 2059

页数：8

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