Synthesis of triphenylpyridines via an oxidative cyclization reaction using Sr-doped LaCoO3 perovskite as a recyclable heterogeneous catalyst

Abstract

An La_0.6Sr_0.4CoO₃ 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 sp³ C–H bond in phenylacetic acid. The La_0.6Sr_0.4CoO₃ catalyst demonstrated a superior performance to that of the pristine LaCoCO₃ as well as a series of homogeneous and heterogeneous catalysts. Furthermore, the La_0.6Sr_0.4CoO₃ 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.