I'm trying to find the mechanism for this reaction:


My (tentative) thought for a possible mechanism is:


EDIT: New thought for mechanism:


But this leaves some loose ends that I haven't been able to figure out. How does the H on OH get removed? (Does it get removed at all?) Most importantly, what is the function of the toluene in this reaction? Why is there a time and temperature given? Any help is greatly appreciated.

  • 1
    $\begingroup$ Toluene is the solvent, that's all. The time and temperature are standard parameters that accompany any reaction description to assist anyone who might want to replicate the reaction. You appear to have a mixture of a radical and ionic mechanism, you might want to decide which it is. $\endgroup$ – Waylander Nov 21 '19 at 18:25
  • $\begingroup$ Thank you for your comment. I now see that the first step of my mechanism doesn't make sense, but even if Br is not a radical, and it forms a bromonium ion on the alkene, I don't see why the OH group suddenly loses its hydrogen and resolves the bromonium positive charge by bonding to the carbon. $\endgroup$ – omzrs Nov 21 '19 at 18:50
  • $\begingroup$ What is the other component present if Br+ is formed from NBS? $\endgroup$ – Waylander Nov 21 '19 at 18:54
  • $\begingroup$ Oh! I think I get it. The nitrogen in NBS now has a lone pair which is basic enough to dehydrogenate the OH group. $\endgroup$ – omzrs Nov 21 '19 at 18:59
  • $\begingroup$ Exactly so, the product is succinimide which precipitates out of the reaction mixture. $\endgroup$ – Waylander Nov 21 '19 at 19:02

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