Site-Selective Functionalization of 7-Azaindoles via Carbene Transfer and Isolation of N-Aromatic Zwitterions.

The first systematic study on metal-carbene transfer reaction of 7-azaindoles has been conducted, and the unprecedented dearomative N7-alkylation reaction has been accomplished via ruthenium catalysis. Importantly, through a sequential dearomatization-aromatization process, an isolable, and new class of azaindole-based N-aromatic zwitterions has been discovered from the reaction of 7-azaindoles and diazoesters.