Dearomative Nucleophilic Addition of Lithium Enolates to Electron-Poor Indoles.

The dearomatization of electron-poor indoles was investigated through the addition of lithiated ester or ketone enolates. Nitro-substituted indoles undergo 1,4-addition to afford the dearomatized products, after smooth hydrolysis. Indoles bearing an α-ketoamide group show a more complex reactivity, undergoing either 1,2- or 1,4-addition, depending on the steric hindrance of the amide group. The regioselectivity of the latter is buttressed by DFT calculations.