P-Chiral thioxaphosphoranesulphenyl chlorides [RR1P(S)SCl]. Unique stereochemical probe for the nucleophilic displacements at the dico-ordinate sulphur

P-Chiral thioxaphosphoranesulphenyl chlorides [RR1P(S)SCI](R =L-menthoxy, R1= EtO) are synthesized in high yield and with optical purity, they are shown to undergo nucleophilic attack at the dico-ordinate sulphur centre by a synchronous mechanism.