Direct Approach to N-Substituted-2-Fluoroindoles by Sequential Construction of C-N Bonds from gem-Difluorostyrenes.

A mild and efficient synthesis of N-substituted-2-fluoroindole derivatives was achieved via Buchwald-Hartwig couplings and a sequential, base-promoted intramolecular nucleophilic reaction-β-fluorine elimination. By employing easily obtained gem-difluorostyrenes and primary arylamines, the scope, advantages, and limitations of this reaction were well investigated. Furthermore, this strategy distinguishes itself by high modularity, operational simplicity, and a wide substrate scope, giving rise to a broad array of 2-fluoroindole derivatives in moderate to excellent yields.