Cyclisation of bis(methylene)phosphoranes: a new way to five-membered heterocycles

Abstract

The catalytic rearrangement of the metallo-bis(methylene)phosphorane 1 in the coordination sphere of an iron atom furnishes two isomeric five-membered heterocycles 2 and 3 resulting from the incorporation of the C₃H₅ ligand and one of the P–C double bonds; a similar reactivity could be obtained in the reaction of the chlorobis(methylene)phosphorane 4 with AlBuⁱ₃, which affords the 1H-λ⁵-methylenephospholane 6.