Studies on the reactivity of 位5-1, 3, 2-diheterophosphacyclanes obtained during the last ten years are examined and described systematically. Data concerning new prototropic and elementotropic processes involving derivatives of pentacoordinate phosphorus are presented. Attention has been concentrated on the elucidation of the influence of the incorporation of a phosphorus(V) atom in the ring on the reactivity of phosphoranes in reactions of various types. The role of phosphorus(V) compounds as intermediates in reactions of phosphorus compounds involving different types of coordination of the phosphorus atom is demonstrated. 漏 1985 IOP Publishing Ltd
