Bis-N-heterocyclic Carbene Aminopincer Ligands Enable High Activity in Ru-Catalyzed Ester Hydrogenation
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- 作者：Georgy A. Filonenko ; Mae Joanne B. Aguila ; Erik N. Schulpen ; Robbert van Putten ; Jelena Wiecko ; Christian M眉ller ; Laurent Lefort ; Emiel J. M. Hensen ; Evgeny A. Pidko
- 刊名：Journal of the American Chemical Society
- 出版年：2015
- 出版时间：June 24, 2015
- 年：2015
- 卷：137
- 期：24
- 页码：7620-7623
- 全文大小：335K
- ISSN：1520-5126
文摘
Bis-N-heterocyclic carbene (NHC) aminopincer ligands were successfully applied for the first time in the catalytic hydrogenation of esters. We have isolated and characterized a well-defined catalyst precursor as a dimeric [Rub>2 b>(L)b>2 b>Clb>3 b>]PFb>6 b> complex and studied its reactivity and catalytic performance. Remarkable initial activities up to 283鈥?00 h鈥? were achieved in the hydrogenation of ethyl hexanoate at only 12.5 ppm Ru loading. A wide range of aliphatic and aromatic esters can be converted with this catalyst to corresponding alcohols in near quantitative yields. The described synthetic protocol makes use of air-stable reagents available in multigram quantities, rendering the bis-NHC ligands an attractive alternative to the conventional phosphine-based systems.