Direct C-H bond arylation: selective palladium-catalyzed C2-arylation of N-substituted indoles

Org Lett. 2004 Aug 19;6(17):2897-900. doi: 10.1021/ol0490072.


We present a new, practical method by which N-substituted indoles may be selectively arylated in the C2-position with good yields, low catalyst loadings, and a high degree of functional group tolerance. Our investigation found that two competitive processes, namely, the desired cross-coupling and biphenyl formation, were operative in this reaction. A simple kinetic model was formulated that proved to be instructive and provided useful guidelines for reaction optimization; the approach described within may prove to be useful in other catalytic cross-coupling processes.