Template Catalysis by Metal–Ligand Cooperation. C–C Bond Formation via Conjugate Addition of Non-activated Nitriles under Mild, Base-free Conditions Catalyzed by a Manganese Pincer Complex
作者:Alexander Nerush、Matthias Vogt、Urs Gellrich、Gregory Leitus、Yehoshoa Ben-David、David Milstein
DOI:10.1021/jacs.5b13208
日期:2016.6.8
The first example of a catalytic Michael addition reaction of non-activated aliphatic nitriles to α,β-unsaturated carbonyl compounds under mild, neutral conditions is reported. A new de-aromatized pyridine-based PNP pincer complex of the Earth-abundant, first-row transition metal manganese serves as the catalyst. The reaction tolerates a variety of nitriles and Michael acceptors with different steric
报道了在温和、中性条件下非活化脂肪腈与 α,β-不饱和羰基化合物的催化迈克尔加成反应的第一个例子。地球丰富的第一排过渡金属锰的一种新的脱芳构化吡啶基 PNP 钳形配合物用作催化剂。该反应耐受具有不同空间特征和受体强度的各种腈和迈克尔受体。包括温度依赖性 NMR 光谱和 DFT 计算在内的机理研究表明,烷基腈的协同活化导致金属化腈亲核物质(α-氰基碳负离子类似物)的产生,是该机制的关键步骤。金属中心不直接参与催化键的形成,而是与配体合作,作为底物活化的模板。这种“模板催化”方法扩大了共轭加成反应的潜在供体范围。