2‐Cyano‐2‐cyclohexylideneacetic acid (1) is heated and $\ce{CO2}$ is lost:

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Why is this not formed?


In other words, why do π-electrons move into the ring?

  • $\begingroup$ As drawn, the reaction will not work. Conceptually, if you lose H+ from -CO2H and then lose CO2 you are left with the anion of the nitrile. Add the proton on the anion and you have CO2 and 2-cyclohexylacetonitrile. There is no double bond. $\endgroup$
    – user55119
    Jan 21, 2021 at 22:59
  • $\begingroup$ Oh I see what has happened. I think someone editing the question has copied one of the molecules incorrectly. I am changing that now. $\endgroup$
    – rdx
    Jan 22, 2021 at 11:11
  • $\begingroup$ You need to ping @user55119, or else they won't get a notification. $\endgroup$ Jan 22, 2021 at 14:20
  • $\begingroup$ This reaction is an Organic Syntheses prep;orgsyn.org/Result.aspx?ga=pa KOH was not used. Now you can work on a mechanism. Notice that ammonium acetate is still present during the decarboxylation. BTW, I believe this very question was asked previously on ChemSE. $\endgroup$
    – user55119
    Jan 22, 2021 at 16:33