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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: jj74 on November 12, 2010, 06:44:31 AM

Title: Alkene equilibration Z-->E
Post by: jj74 on November 12, 2010, 06:44:31 AM

I came across this in Clayden organic chemistry. One of the way to equilibrate Z-alkene to E-alkene is addition of iodine to the double bond (reaction in attachement). What is not explained is how I go back to the olefin (E) when I have the diiodo derivate. Is there any particular reagent/method ?
thanks

Title: Re: Alkene equilibration Z-->E
Post by: AWK on November 12, 2010, 07:10:10 AM

This is rather catalysis, and not addition.

Title: Re: Alkene equilibration Z-->E
Post by: jj74 on November 12, 2010, 07:50:54 AM

so iodine goes away spontaneously after rotation?

Title: Re: Alkene equilibration Z-->E
Post by: MOTOBALL on November 13, 2010, 10:24:49 AM

My recollection is that I₂ adds very readily to >C=C<, but that vicinal di-iodo compounds are very unstable and will readily eliminate I₂ spontaneously to give the -ene.

Thus the equilibrium condition is established very quickly.