A Pragmatic Radical Strategy for Dearomative Hydroalkylation of Unactivated Indoles

Dearomative functionalization offers a direct approach for transforming planar aromatics into C(sp³)-rich frameworks with potentially improved drug-like properties. Herein, we report a metal-free and operationally simple method with broad functional group tolerance for the dearomative hydroalkylation of indoles using alkyl boronates. This strategy advances the radical-based dearomatization strategy to previously unreactive indole substrates, enabling access to a variety range of three-dimensional indolines. Notably, it highlights the use of transient indolenium ions in radical-mediated C-C bond formation, establishing a new platform for rapidly diversifying indole-derived scaffolds.