[Dolphinsiu]

cis-1,2-dibromocycloheane + KI ---> debromination product!

stereospecific ??

My teacher says it is stereospecific. Why it is stereospecific?

I still feel confused in definition of stereospecific

[madscientist]

I think it might have somthing to do with the less sterically hindered (less crowded) site for debromination on the reagent.

[PRIYA1022]

Is it debromination or dehydrobromination? I have never come across a debromination in presence of KI. And are you sure your teacher was referring to KI in that "stereospecific reaction" ?

[english]

Stereospecific means one isomer of the reactant can lead to one set of stereoisomers, and another isomer of that reactant can lead to a different set of stereoisomers.

[Ψ×Ψ]

This might also clear things up.

[Dolphinsiu]

   I^- -->Br
          /
   / \ / /
  /     /  Br -->
 / /\  / /
 /   

---> (Z)-cyclohexene + IBr + Br-

This is my notes.

If trans-form is used, (E)-cyclohexene is formed. I now know why it is stereospecific! Thank you!

[PRIYA1022]

Can you have E and Z-CYCLOHEXENE?...
(There cannot be a trans double bond in a six membered cyclic compound.)
Are you sure you have it right in your notes???

[Ψ×Ψ]

There can't be a TRANS-cyclohexene.  E and Z nomenclature refers to the relative position of the highest priority groups.  Depending on the substituent, I think a substituted E-cyclohexene is possible.

[Dolphinsiu]

My notes says that it is two-step process: substitution of Br- by I- + Elimination for both Br- and I-.

Is it really stereospecific to your knowledge?