TOTALLY STEREOSELECTIVE P-O TO P-C MIGRATION REARRANGEMENT - APPLICATION TO THE SYNTHESIS OF NEW CHIRAL O-HYDROXYARYL PHOSPHINE OXIDES

The synthesis of a novel class of chiral o-hydroxyaryl phosphine oxide s by the rearrangement of a P - O to a P - C bond is described. This r eaction proceeds with excellent yields (75-95%) and total retention of the configuration on the phosphorus atom. In the case of the treatmen t of an equimolar mixture of the diastereomers anti-2e and syn-2f, the resulting compounds anti-3e and syn-3f, obtained in a 1:1 molar ratio ? were separated and characterized by X-ray diffraction. On the basis of the experimental results, we suggest that the migration mechanism i s addition- pseudorotation- elimination; this explains the total stere oselectivity observed at the phosphorus atom.