Dearomatization of 3-Nitroindoles by a Phosphine-Catalyzed Enantioselective [3+2] Annulation Reaction.

The dearomatization of 3-nitroindoles through a chiral-phosphine-mediated [3+2] annulation reaction is described. This method makes use of readily available 3-nitroindoles as an aromatic feedstock and rapidly delivers a wide range of cyclopentaindoline alkaloid scaffolds in a highly enantioselective manner. Notably, phosphine-triggered cyclization has not been utilized previously in a dearomatization process.