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I was trying to look-up the mechanism of reaction of organic compounds with SeO2, but I am not able to understand it. I would really appreciate if someone can predict the end product with the mechanism.

I am getting 2-oxo-propan-1-al (I hope the nomenclature is correct), as a product. But I have a doubt, will it react further, because it could still exist as a enol (2-Hydroxy-prop-2-en-1-al), which can further undergo the reaction with SeO2.

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  • $\begingroup$ A ketone can also be considered as an enol. After that I guess you should find something usefull. I'm on a train I have no paper to do it but I think it can helps. At the end you must obtain SeOH too. $\endgroup$
    – ParaH2
    Commented Jul 11, 2016 at 20:55
  • $\begingroup$ @Shadock Thanks a lot! I tried, and I am getting 2-oxo-propan-1-al (I hope the nomenclature is correct), as a product. But I have a doubt, will it react further, because it could still exist as a enol (2-Hydroxy-prop-2-en-1-al), which can further undergo the reaction with SeO2. $\endgroup$
    – AnonMouse
    Commented Jul 11, 2016 at 21:15
  • $\begingroup$ It probably depends on how much SeO2 you have inside there. At least, I am not aware of anything stopping the other methyl group from being oxidised as well. For the SeO2 oxidation of alkenes, as far as I know, both the initial allylic alcohol product as well as the final (doubly oxidised) a,b-unsaturated ketone can be formed depending on the conditions. For this question I would assume that the reaction stops after a single oxidation. Btw @Shadock it's Se(OH)2 not SeOH. $\endgroup$
    – orthocresol
    Commented Jul 11, 2016 at 21:29
  • $\begingroup$ @orthocresol As per the solutions given in the text, only one CH3 undergoes oxidation, even though excess SeO2 is provided. I still don't understand the reason for this. Does steric or electronic factors contribute? $\endgroup$
    – AnonMouse
    Commented Jul 11, 2016 at 21:31
  • $\begingroup$ Sorry, I don't know. $\endgroup$
    – orthocresol
    Commented Jul 11, 2016 at 21:32

1 Answer 1

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Well I guess that is not a perfect solution but I think you will improve it easely if your are studying organic chemistry. I"ll try to make a beautiful picture with chemdraw when i'll have time.

Oxydation of a ketone with SeO2

Remember that you can always draw an enol when you have a ketone. If you have no idea at first with the ketone, try it with the enol.

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    $\begingroup$ Thanks a lot for this. I think the cyclic intermediate stage increases kinetic factors, and increases the rate. But am I missing something or does the Se atom have only 1 hydroxy group till the 3rd last stage (the other oxygen gets linked to carbon), and then it suddenly has 2 of them in the second last stage? $\endgroup$
    – AnonMouse
    Commented Jul 12, 2016 at 18:23
  • $\begingroup$ How this formed compound react with sodium hydroxide? Does it undergo aldol condensation? $\endgroup$
    – crimsonKn1ght
    Commented Dec 11, 2018 at 15:13

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