Derivatives of NPCl2(NSOCl)2 and (NPCl2)2NSOCl. Part 17. The dimethylaminolysis pattern of cis-NPCl2(NSOCl)2

Abstract

The sequence of chlorine substitution of cis-NPCl₂(NSOCI)₂ by dimethylamine in acetonitrile is S(1)–Cl, P–Cl, S(2)–Cl, P–Cl. The stereoselectivity of the consecutive steps shows similarities with that of the dimethylaminolysis of (NPCl₂)₃, but differs from it by the profound influence of the oxygen ligands, particularly if they are in mutual cis position. The relative weakness of the sulphur–chlorine bond(s) does not only result in an unusual mechanism of the first substitution step, but also in substantial isomerization phenomena as long as such bonds are present in the molecule. The isomerizations contribute considerably to the formation ratio of the products, particularly in reactions with an excess of amine. Isomerizations of selected derivatives can be induced by dimethylamine hydrochloride as well as catalytic amounts of antimony(V) chloride.