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Organic Synthesis

Anybody has any idea how to do this? I tried converting the ketone to a alcohol using Grignard, but I have no idea how to proceed afterwards. I also tried starting with the Wittig reaction by converting to an alkene, but likewise, I dont know how to proceed. I have also tried working backwards, but to no avail as well. Anybody mind helping?

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    $\begingroup$ I'd say we have to functionalize that methyl group first, using the C-H acidity provided by the ketone, and only then destroy the latter. $\endgroup$ – Ivan Neretin Apr 19 '17 at 13:09
  • $\begingroup$ @IvanNeretin wow! totally didn't think of that! but do you have any suggestions on how to destroy it afterwards? $\endgroup$ – Jason Lam Apr 19 '17 at 13:13
  • $\begingroup$ Is this a homework problem or an actual synthesis question? If it's homework, I like @Waylander's answer. If it's for real, I think that won't work, and it's going to be tough with that highly substituted quaternary center. $\endgroup$ – Zhe Apr 19 '17 at 15:44
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React the enolate of pinacolone (t-Bu Methyl ketone) with methyl vinyl ketone. It will first add 1,4 then the resulting enolate will do an aldol on the pinacolone ketone to give 3-tBu-cyclohexenone. React this with Phenyl cuprate and, despite the steric hindrance, it will add Michael-wise to give you the desired product.

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  • $\begingroup$ My first thought was exactly the same, but I find it highly unlikely that you're going to add the phenyl group to a carbon bearing a t-butyl group... $\endgroup$ – Zhe Apr 19 '17 at 15:38
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    $\begingroup$ I share that concern but I have no Scifinder access to check. If you can't do it that way then it becomes a far more complex problem. $\endgroup$ – Waylander Apr 19 '17 at 15:57
  • $\begingroup$ I'm in the same boat regarding a lit search. I really want your answer to be viable because I can't think of an easy way to do this otherwise, either. $\endgroup$ – Zhe Apr 19 '17 at 18:19
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    $\begingroup$ @Zhe, Waylander, I had a look at this on Reaxys today, the exact compound with that heavily hindered quaternary stereo centre isn't found, so I suspect the question is hypothetical $\endgroup$ – NotEvans. Apr 20 '17 at 18:37
  • $\begingroup$ Thank you. This increases my suspicion that the enone is too hindered to undergo the cuprate addition. $\endgroup$ – Waylander Apr 21 '17 at 12:15

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