Unusual Anion Effects in the Iron‐Catalyzed Formation of 3‐Hydroxyacrylates from Aromatic Aldehydes and Ethyl Diazoacetate
作者:Luis Gonçalo Alves、Georg Dazinger、Luis F. Veiros、Karl Kirchner
DOI:10.1002/ejic.201000240
日期:2010.7
Due to the lability of one of the CO ligands in trans-[Fe(PNP)-(CO) 2 CI] + this compound is an efficient catalyst for the coupling of a series of aromatic aldehydes with ethyl diazoacetate (EDA), which give, in most cases, selectively 3-hydroxyacrylates rather than β-oxo esters. This reaction is strongly dependent on the nature of the counterion. Whereas with BF 4 - the reaction proceeds with conversions
由于反式-[Fe(PNP)-(CO) 2 CI] + 中的一个 CO 配体的不稳定性,该化合物是一系列芳香醛与重氮乙酸乙酯 (EDA) 偶联的有效催化剂,可生成在大多数情况下,选择性地使用 3-羟基丙烯酸酯而不是 β-氧代酯。该反应强烈依赖于反离子的性质。而对于 BF 4 - 反应以高达 90% 的转化率进行,对于反离子 NO 3 - 、CF 3 COO - 、CF 3 SO 3 - 、SbF 6 - 和 BAr' 4 - [Ar' = 3 ,5-(CF 3 ) 2 C 6 H 3 ]没有反应发生。在 PF 6 的情况下,仅实现了高达 20% 的转化率。通过 DFT/B3LYP 计算建立了芳香醛与 EDA 偶联的可能机制,这使得化学选择性和抗衡离子的作用合理化。