New and Efficient Palladium(0)-Mediated Microwave-Assisted Direct C3 Alkenylation of Imidazo[1,2-a]pyridines.

In this paper, we present the synthesis of 3-alkenylimidazo[1,2- A]pyridines in high to moderate yields by microwave direct palladium-catalyzed C-H alkenylation between bromoalkenes and imidazo[1,2- A]pyridines. The scope and limitation of the palladium(0)-catalyzed alkenylation method were investigated. Optimized conditions were successfully applied to a wide variety of imidazo[1,2- A]pyridine derivatives and bromoalkenes. The compatibility of the synthesis with the presence of a chloro substituent in the 6-position was investigated. The 6-chloroimidazo[1,2- A]pyridines were functionalized using Suzuki cross-coupling conditions to give polyfunctional compounds. [ABSTRACT FROM AUTHOR]