Organophosphorus compounds XI: Stereochemistry of grignard displacement reactions at phosphorus in isopropyl methylphosphonohalogenates

A series of stereospecific reactions, starting from (−)-(isoPrO)MeP(O)H (I) (see Reaction Scheme), establishes that the absolute configuration of (+)-(isoPrO)-MeP(O)SMe(II) (R′=Me) is (R), and not (S) as previously suggested. The reassigned configuration is confirmed by X-ray analysis. It follows that the displacement of X by Ph in isoPrO(Me)P(O)X proceeds with complete retention of configuration when X = SMe, but proceeds with complete inversion when X = F. In the case of X = Cl, the reaction proceeds at least predominantly with inversion of configuration.