Dialkylamino cyclopentadienyl ruthenium(<scp>ii</scp>) complex-catalyzed α-alkylation of arylacetonitriles with primary alcohols
作者:Hung Wai Cheung、Juan Li、Wenxu Zheng、Zhongyuan Zhou、Yu Hin Chiu、Zhenyang Lin、Chak Po Lau
DOI:10.1039/b917805h
日期:——
Aminocyclopentadienyl ruthenium complexes, [(η5-C5H4NMe2)Ru(PPh3)2(CH3CN)]+BF4â and [(η5-C5H4NEt2)Ru(PPh3)2(CH3CN)]+BF4â, are moderately active catalysts for α-alkylation of arylacetonitriles with primary alcohols; on the other hand, the analogous unsubstituted cyclopentadienyl ruthenium complex [(η5-C5H5)Ru(PPh3)2(CH3CN)]+BF4â shows very low catalytic activity. On the basis of experimental results and theoretical calculations, rationalization for the much higher catalytic activity of the aminocyclopentadienyl complexes over that of the unsubstituted Cp complex is provided. In the catalytic systems with the former, it is possible to regenerate the active solvento complexes via protonation of the metal hydride intermediates and subsequent ligand substitution; this process is, however, very nonfacile in the catalytic system with the latter.
Chemoselective α-Alkylation and α-Olefination of Arylacetonitriles with Alcohols <i>via</i> Iron-Catalyzed Borrowing Hydrogen and Dehydrogenative Coupling
borrowing hydrogen or α-olefination by dehydrogenativecoupling methods. Designing and developing high-performance earth-abundant catalysts that can procure different products from the same starting materials remain a great challenge. Herein, we report an iron(0) catalyst system that achieves chemoselectivity between borrowing hydrogen and dehydrogenativecoupling protocols by simply changing the base. A
α-烷基腈和α-烯烃腈在有机合成和药物化学中非常重要。然而,不同类型的催化剂用于通过借氢实现腈的α-烷基化或通过脱氢偶联方法实现α-烯烃化。设计和开发高性能的地球丰富的催化剂,可以从相同的起始材料中获得不同的产品仍然是一个巨大的挑战。在此,我们报告了一种铁 (0) 催化剂系统,该系统通过简单地改变碱基来实现借氢和脱氢偶联方案之间的化学选择性。广泛的腈类和醇类,包括苄醇、直链脂肪醇、脂环醇、杂环醇和烯丙醇,被选择性且有效地转化为相应的产物。机理研究表明反应机理通过脱氢途径进行。这种铁催化方案对环境无害且原子效率高,可释放 H2和 H 2 O 作为绿色副产物。