I need some help understanding the hypervalent iodine phenolic coupling reaction taking place in this synthesis of morphine, the reaction uses $\ce{PhI(OAc)2}$ as the hypervalent reagent and trifluoroethanol as a solvent.

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  1. What is the mechanism taking place here? From my understanding the hypervalent compound contains a 3c-4e bond in which the iodide bears the positive charge and therefore is what the lone pair on the $\ce{-OH}$ attacks, what takes place after this?

  2. This reaction results in the dearomatisation of one of the phenol rings, isn't a dearomatised ring a thermodynamically more unstable product, what is driving this reaction?

  3. The paper describes the trifluoroethanol solvent as crucial, what makes the use of this solvent crucial? Is it the lack of nucleophilicity preventing a reaction with the iodine reagent?

The paper I am looking at is this one for reference.

  • 1
    $\begingroup$ Welcome to ChemSE! Your question will likely be considered as homework. You need to make some effort to answer the question yourself . Take a look here about homework policy. chemistry.meta.stackexchange.com/questions/141/…. Try searching "phenolic coupling". $\endgroup$
    – user55119
    Commented Jan 11, 2021 at 15:21
  • 4
    $\begingroup$ I don’t think this is homework. $\endgroup$ Commented Jan 11, 2021 at 15:46


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