Carbolithiation of Vinyl Pyridines as a Route to 7-Azaindoles

Significance

This paper provides a new and efficient synthetic route to functionalized 7-azaindoles. The Suzuki carbolithiation/intramolecular Madelung-type sequence leads to indoles with R² = n,- s-, t-Bu and R³ = Ph, t-Bu, C₄H₃S groups with little variation at R¹ = H, Me substitution. It is a considerable improvement over several other methods for the synthesis of 2,3-substituted indoles such as Fischer indole and Madelung reactions.