Water-enabled α-C(sp3)–H amination via [1,6]-hydride transfer: green access to diazepino[6,5,4-cd]indoles

Abstract

Water is an ideal green reaction medium in organic synthesis, and the development of water-enabled transformations to synthesize high value-added molecules is particularly attractive but challenging. Herein, we disclosed the water-enabled α-C(sp³)–H amination of 4-dialkylamino-indole-3-carbaldehydes with primary amines for one-step green synthesis of diazepino[6,5,4-cd]indole derivatives. This reaction proceeded via a cascade aldimine condensation/[1,6]-hydride transfer/cyclization sequence, which featured redox-neutral conditions, water as the green reaction medium, simple operation, high atom- and step-economy, and excellent functional group tolerance.