RWTH Aachen University, Institute of Organic Chemistry, Landoltweg 1, D-52074 Aachen, Germany.
J Am Chem Soc. 2013 Feb 6;135(5):1823-9. doi: 10.1021/ja309580a. Epub 2013 Jan 18.
Visible light photoredox catalyzed inter- and intramolecular C-H functionalization reactions of tertiary amines have been developed. Oxygen was found to act as chemical switch to trigger two different reaction pathways and to obtain two different types of products from the same starting material. In the absence of oxygen, the intermolecular addition of N,N-dimethyl-anilines to electron-deficient alkenes provided γ-amino nitriles in good to high yields. In the presence of oxygen, a radical addition/cyclization reaction occurred which resulted in the formation of tetrahydroquinoline derivatives in good yields under mild reaction conditions. The intramolecular version of the radical addition led to the unexpected formation of indole-3-carboxaldehyde derivatives. Mechanistic investigations of this reaction cascade uncovered a new photoredox catalyzed C-C bond cleavage reaction.
可见光光氧化还原催化的三级胺的分子间和分子内 C-H 功能化反应已经被开发出来。研究发现，氧气可以作为化学开关，触发两种不同的反应途径，并从相同的起始原料中获得两种不同类型的产物。在没有氧气的情况下，N,N-二甲基苯胺与缺电子烯烃的分子间加成反应以良好到高产率提供γ-氨基酸腈。在氧气存在的情况下，发生自由基加成/环化反应，在温和的反应条件下以良好的产率得到四氢喹啉衍生物。自由基加成的分子内版本导致吲哚-3-甲醛衍生物的意外形成。对这种反应级联的机理研究揭示了一种新的光氧化还原催化的 C-C 键断裂反应。
