Synfacts 2009(12): 1327-1327  
DOI: 10.1055/s-0029-1218220
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart ˙ New York

Cascade N-Annulation Route to 7-Azaindoles

Contributor(s): Victor Snieckus, Toni Rantanen
R. C. Hodgkinson, J. Schulz, M. C. Willis*
University of Oxford and Schering Plough Corporation, Newhouse, UK
Further Information

Publication History

Publication Date:
20 November 2009 (online)

Significance

Described is how a series of 3-(2-haloalkenyl)-2-pyridyl halides undergo consecutive Pd-catalyzed inter- and intramolecular aminations to furnish 7-azaindoles. Furthermore, one example of 6- and 4-azaindole synthesis was given. The reactions employ normal Pd-catalyzed amination conditions, and the yields range mostly from moderate to good. 2-Chloropyridines were the exception, affording lower yields or no reaction. It was shown that the choice of the correct ligand plays a crucial role, as for example a change from SPhos to dppf increased the yield of one substrate from 0 to 64%. The substrate scope was well studied in terms of the amine, less so with the pyridine component.