Tang Shan, Milstein David
Department of Organic Chemistry , The Weizmann Institute of Science , Rehovot 76100 , Israel . Email:
Chem Sci. 2019 Aug 7;10(39):8990-8994. doi: 10.1039/c9sc03269j. eCollection 2019 Oct 21.
Activation of C[triple bond, length as m-dash]N bonds by metal-ligand cooperation provides a new route for the functionalization of nitriles. Herein, we report the electrophilic activation of unsaturated nitriles by dearomatized manganese pincer complexes for the oxa- and aza-Michael addition reactions under very mild and neutral conditions. Derivatives of acrylonitrile and allyl cyanide furnished the corresponding β-addition products by reacting with alcohols and amines. Mechanistically, the catalysis is mostly ligand based. Reaction of the dearomatized PNN-Mn complex with 2-pentenenitrile or 3-pentenenitrile furnished an enamido-Mn complex. The equilibrium between an enamido complex and a ketimido complex, and reversible C-C bond formation with the ligand are proposed to play central roles in the catalysis.
通过金属-配体协同作用活化碳氮三键为腈的官能团化提供了一条新途径。在此，我们报道了去芳构化锰钳形配合物在非常温和且中性的条件下对不饱和腈进行亲电活化以实现氧杂和氮杂迈克尔加成反应。丙烯腈和烯丙基腈的衍生物通过与醇和胺反应得到相应的β-加成产物。从机理上讲，催化作用主要基于配体。去芳构化的PNN-Mn配合物与2-戊烯腈或3-戊烯腈反应生成了烯酰胺基-Mn配合物。烯酰胺基配合物与酮亚胺基配合物之间的平衡以及与配体的可逆碳-碳键形成被认为在催化过程中起核心作用。
