A highly active FeNi3-SiO2 magnetic nanoparticles catalyst for the preparation of 4H-benzo[b]pyrans and Spirooxindoles under mild conditions

A green and efficient method for the synthesis of various 4H-benzo[b]pyrans and Spirooxindoles in the presence of FeNi3-SiO2 as the nanocatalyst at room temperature is reported. High catalytic activity and ease of recovery from the reaction mixture using an external magnet, and several reuse times without significant losses in performance are additional eco-friendly attributes of this catalytic system.