Synthesis of triphenylpyridines via an oxidative cyclization reaction using Sr-doped LaCoO 3 perovskite as a recyclable heterogeneous catalyst.

An La 0.6 Sr 0.4 CoO 3 strontium-doped lanthanum cobaltite perovskite was prepared via a gelation and calcination approach and used as a heterogeneous catalyst for the synthesis of triphenylpyridines via the cyclization reaction between ketoximes and phenylacetic acids. The transformation proceeded via the oxidative functionalization of the sp 3 C-H bond in phenylacetic acid. The La 0.6 Sr 0.4 CoO 3 catalyst demonstrated a superior performance to that of the pristine LaCoCO 3 as well as a series of homogeneous and heterogeneous catalysts. Furthermore, the La 0.6 Sr 0.4 CoO 3 catalyst was facilely recovered and reused without considerable decline in its catalytic efficiency. To the best of our knowledge, the combination of ketoximes with easily available phenylacetic acids is novel.