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Also find the order of the rates of the given reactions.

Answer: The answer of this question is given as option 'D' ie. all products are identical, however I am getting the answer as option 'C'.

My approach: I figured out that the under the presence of the given reagent the substrates will undergo elimination reaction via the E2 mechanism, in reactions (2) and (3), the same alkenes will be formed and the ketone will tautomerise to form a highly stable phenol, but in the first reaction I made Cyclohex-2,5-dien-one as the product, I am not able to understand how will this covert to phenol?

For the comparison of the rates I figured out that reaction (2) will have the fastest rate due to a highly acidic hydrogen present (the anion formed is in extended resonance with the double bond and the ketone), however I am not able to compare between the rates of the first and the third reactions.

Am I thinking in the right direction or is there some mistake? Please help.

  • $\begingroup$ @Karl Can you explain by a diagram? I did not get what you wrote. $\endgroup$
    – Shriom707
    Sep 6, 2020 at 18:10
  • $\begingroup$ Nope, your homework: Draw the detailed step-by-step diagram of the keto-enol step in (2) and (3), then try to do sth. very similar with (1). ;-) $\endgroup$
    – Karl
    Sep 6, 2020 at 18:21
  • $\begingroup$ @Karl thank you , I got the answer as phenol $\endgroup$
    – Shriom707
    Sep 6, 2020 at 18:35
  • $\begingroup$ Can you comment on the rates of the reactions? $\endgroup$
    – Shriom707
    Sep 6, 2020 at 18:35
  • $\begingroup$ No clue, honestly. Zilch. But there are others around here who are smarter in OC than me. ;-) $\endgroup$
    – Karl
    Sep 6, 2020 at 18:38


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