Mild and Selective Ru-Catalyzed Formylation and Fe-Catalyzed Acylation of Free (N–H) Indoles Using Anilines as the Carbonyl Source
摘要:
C3-selective formylation and acylation of free (N-H) indoles under mild conditions can be achieved by using Ru- and Fe-catalyzed oxidative coupling of free (N-H) indoles with anilines, respectively. Both processes are operationally simple, compatible with a variety of functional groups and generally provide the desired products in good yields. (13)C-labeling experiments unambiguously established that the carbonylic carbon in the formylation products originated from methyl group of N-methyl aniline.
In order to synthesize the intermediates of cannabimimetics, the benzoylation of indoles with 2'/3'/4'-substituted benzoyl chloride in the presence of Et2AlCl was examined. Among the products, we found that the H-1 NMR spectra of 3-(2'-substituted)-benzoyl-2-methylindoles had interesting features. We investigated their physicochemical properties based on VT-NMR, and it was revealed that conformer A (s-trans) is present in preference to conformer B in these compounds.