Reactivity of phosphiranes toward nucleophiles: Theoretical and experimental investigations

Abstract

The thermodynamic and kinetic parameters for the reaction of 1-methylphosphirane with dimethylphosphide (PMe2-), proceeding via attack at the ring phosphorus atom to give Me2P- PMe- plus ethylene, were calculated at the G3(MP2)-RAD(+) level. The rate constant for this mechanism (k= 1.1 × 10-13 L mol -1 s-1 at 25°C) is seven orders of magnitude greater than that for the previously studied mechanism involving attack at carbon. Experimental investigations with 1-phenylphosphirane gave consistent results: Treatment with LiPMePh yielded no detectable polymer, and quenching with MeI gave the known diphosphine (R*, R*)-(±)/(R*,S*)- MePhP-PMePh. © 2008 Wiley Periodicals, Inc.