Pd(II)-Catalyzed Regioselective 2-Alkylation of Indoles via a Norbornene-Mediated C–H Activation: Mechanism and Applications

http://pubs.acs.org/doi/full/10.1021/ja3058138

Lei Jiao, Eberhardt Herdtweck, and Thorsten Bach Journal of the American Chemical Society Article ASAP

This thorough paper outlines a method for functionalizing indoles using catalytic amounts of palladium in the presence of excess norbornene. They probe the mechanism of this transformation using NMR spectroscopy, isotope labeling and trapping experiments. They identify and isolate an interesting palladacyclic intermediate shown in the above figure. They then apply this chemistry to the total synthesis of Aspidospermidine and Goniomitine, two indole alkaloids.