Iron-Catalyzed C3-Formylation of Indoles with Formaldehyde and Aqueous Ammonia under AirWe thank the National High Technology Research and Development Program of China (2007AA02Z301), the Natural Science Foundation of Jiangsu Province (BK20141257), the Natural Science Foundation of Yancheng Teachers University (09YCKL021, 14YCKL001), and the Fundamental Research Funds for the Central University (WY111307) for their generous financial support
Received: 22 May 2017
Accepted after revision: 23 June 2017
14 August 2017 (eFirst)
An efficient iron-catalyzed C3-selective formylation of free (N–H) or N-substituted indoles was developed by employing formaldehyde and aqueous ammonia, with air as the oxidant. This new method gave 3-formylindoles in moderate to excellent yields with fairly short reaction times. Moreover, this procedure for catalytic formylation of indoles can be applied to gram-scale syntheses.