Sulfur oxochlorides

In Section 6.15, we will encounter SO2CI2 again, in the role of an oxidant in the synthesis 

The main industrial synthesis of SOCI2 is based on the reaction of SO3 and SCI2  

This is an example of an oxygen atom transfer (OAT) reaction. In other words, the reaction results in the net transfer of one oxygen from SO3 to SCI2. The question now is is it a direct OAT, as shown in the mechanism below  

An awkward feature of this mechanism is that the electrophile is an oxygen atom with a formal charge of -1 We therefore searched around for alternative mechanisms. 

A simple way to avoid SCI2 attack an anionic oxygen is to have it attack the doubly bonded oxygen, as shown below  

---

SULFUR OXOCHLORIDES 221 Two successive chloride ion migrations from P to S would then yield the observed products ... 

The range of sulfur chlorides and oxochlorides (which are aU hydrolysed by water) is far more restricted than that of the corresponding fluorides, and there are no stable chloro-analogues of SF4, SFg and S2F10. One example of a high oxidation state chloride is SCIF5, prepared as shown in Figure 15.12. 

---