A Metal-Ligand Cooperative Pathway for Intermolecular Oxa-Michael Additions to Unsaturated Nitriles
作者:Sébastien Perdriau、Douwe S. Zijlstra、Hero J. Heeres、Johannes G. de Vries、Edwin Otten
DOI:10.1002/anie.201412110
日期:2015.3.27
activation of the nitrile through metal–ligand cooperativity is a key step. The nitrile‐derived Ru‐N moiety is sufficiently Brønsted basic to activate the alcohol and initiate conjugate addition of the alkoxide to the α,β‐unsaturated fragment. This reaction proceeds in a concerted manner and involves a six‐membered transition state. These features allow the reaction to proceed at ambient temperature in the
使用具有脱芳族化吡啶骨架的PNN钳形钌催化剂,发现了醇类向不饱和腈的oxa-Michael加成反应的前所未有的催化途径。从Ru催化剂和戊烯腈之间的反应中分离出具有催化活性的Ru-二烯酰胺基配合物,结合DFT计算,支持了一种机制,其中通过金属-配体的协同作用活化腈是关键的一步。腈衍生的Ru-N部分具有足够的Brønsted碱性,可以活化醇并引发醇盐与α,β-不饱和片段的共轭加成。该反应以协调的方式进行,并涉及六元过渡态。这些特征允许反应在环境温度下在没有外部碱的情况下进行。