Selective iron-catalyzed cross-coupling reactions of Grignard reagents with enol triflates, acid chlorides, and dichloroarenes
Selective iron-catalyzed cross-coupling reactions of Grignard reagents with enol triflates, acid chlorides, and dichloroarenes
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DOI：
10.1021/jo0498866
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发表时间：
2004-05-28
影响因子：
3.6
通讯作者：
Fürstner, A
中科院分区：
文献类型：
--
作者：
Scheiper, B;Bonnekessel, M;Fürstner, A
廉价、易得、空气稳定、无毒且环境友好的铁盐（例如 Fe(acac)(3)）是格氏试剂与烯基三氟甲磺酸酯和酰基氯交叉偶联的优异预催化剂。此外，表明作为底物的二氯芳烃和杂芳烃衍生物可以通过该方法选择性地单烷基化。所有交叉偶联反应在特别温和的条件下都进行得非常快，并且与两个反应伙伴中的各种官能团相容。对制备结果的详细分析表明，铁催化的 C-C 键形成可以通过不同的途径发生。因此，甲基卤化镁的反应很可能涉及铁酸盐络合物作为活性组分，而具有两个或多个碳原子的格氏试剂的反应是通过原位生成的形式组合物[Fe(MgX)(2)](n)的高度还原的铁簇实现的。使用 ate 复合物 [Me4Fe]Li-2 的对照实验证实了这一解释。
Cheap, readily available, air stable, nontoxic, and environmentally benign iron salts such as Fe(acac)(3) are excellent precatalysts for the cross-coupling of Grignard reagents with alkenyl triflates and acid chlorides. Moreover, it is shown that dichloroarene and -heteroarene derivatives as the substrates can be selectively monoalkylated by this method. All cross-coupling reactions proceed very rapidly under notably mild conditions and turned out to be compatible with a variety of functional groups in both reaction partners. A detailed analysis of the preparative results suggests that iron-catalyzed C-C bond formations can occur via different pathways. Thus, it is likely that reactions of methylmagnesium halides involve iron-ate complexes as the active components, whereas reactions of Grignard reagents with two or more carbon atoms are effected by highly reduced iron-clusters of the formal composition [Fe(MgX)(2)](n) generated in situ. Control experiments using the ate-complex [Me4Fe]Li-2 corroborate this interpretation.