-3-Azido-2-methoxyindolines as safe and stable precursors to overcome the instability of fleeting 3-azidoindoles.

Use of 3-azidoindoles in organic synthesis remains a difficult task owing to their instabilities. Herein, we report a general and concise approach for tackling this problem by using 3-azidoindole surrogates. The surrogates are bench-stable, presumably due to the observed intramolecular O-N bonding. The resultant fleeting intermediates undergo capturing to afford 3-substitued indoles through formal -substitution of the azide group by nucleophiles. In these investigations, we found that the fleeting 3-azidoindoles show a C3-electrophilic character for the first time.