Kinetic Study of Phosphoranes Formation by Oxidative Addition of Aliphatic Alcohols on Monocyclic Phospholanes

Taoufik Boubakera¹, Maric-Therese Boisdonb², Rachida Bessrourc³ and Bahoueddine Tangour¹*

¹Faculty of Sciences, Avenue del' environment, 5000 Monastir, (Tunisia) ²Universite' Paul Sabateir, 118 Route de Narbonne, Rangueil, Touiouse, (France) ³Faculty of Sciences, Tunis, 1060 Le Belvedere, (Tunisia)

The oxidative addition of aliphatic alcohol on monocyclic phospholanes leads to the formation of monocyclic phosphoranes with P-H bond in equilibrium with the starting materials. The kinetic of formation has been studied by several techniques. In all experimental requirements, the reactions follow second order kinetics first order with respect to both phospholane and alcohol. Kinetic parameters have been determined. Gibbs free enthalpy of transition state formation is nearly equal to 85 KJ.mol-1. Isotopic effect suggests that phosphorus lone pair attack on hydrogen atom of the hydroxyl group is the determining step. The entropy variation indicates that this step leads to the formation of pseudo-phosphonium ion as reaction intermediate.

Oxidative addition on phospholanes; Phosphoranes with P-H bond; Phosphonium ion; Biphily