Nguyen Suong T, Zhu Qilei, Knowles Robert R
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
ACS Catal. 2019 May 3;9(5):4502-4507. doi: 10.1021/acscatal.9b00966. Epub 2019 Apr 17.
Olefin aminations are important synthetic technologies for the construction of aliphatic C-N bonds. Here we report a catalytic protocol for olefin hydroamidation that proceeds through transient amidyl radical intermediates that are formed via proton-coupled electron transfer (PCET) activation of the strong N-H bonds in -alkyl amides by an excited-state iridium photocatalyst and a dialkyl phosphate base. This method exhibits a broad substrate scope, high functional group tolerance, and amenability to use in cascade polycyclization reactions. The feasibility of this PCET protocol in enabling the intermolecular anti-Markovnikov hydroamidation reactions of unactivated olefins is also demonstrated.
烯烃胺化反应是构建脂肪族C-N键的重要合成技术。在此,我们报道了一种烯烃氢酰胺化的催化方法,该方法通过瞬态酰胺基自由基中间体进行,这些中间体是由激发态铱光催化剂和磷酸二烷基酯碱通过质子耦合电子转移(PCET)活化α-烷基酰胺中强N-H键而形成的。该方法具有广泛的底物范围、高官能团耐受性,并且适用于级联多环化反应。还证明了这种PCET方法在实现未活化烯烃的分子间反马氏氢酰胺化反应中的可行性。