One-pot synthesis of tetrahydro benzo[b]pyran derivatives using iron ore pellet as natural, efficient and reusable heterogeneous catalyst in aqueous media

An efficient synthesis of tetrahydro benzo[b]pyran derivatives is achieved via a tree-component reaction of aldehydes, dimedone and malononitrile in the presence of iron ore pellet as natural catalyst in water. The key advantages are the short reaction time, high yields, simple workup, and green media. The catalyst can be recovered by simple filtration and reused at least seven cycles without losing its activities