I have this task to do:enter image description here

My solution: enter image description here

Is that possible? Can you please help me with the steps 2 and 3?

This is what I did, but my teacher told me I should make the diketone (compound no. 5) from the starting compound (allyl bromide) by Grignard reaction:

enter image description here

  • $\begingroup$ I think your endgame is good (from aldol through the end). There is probably another way to get to pentane-2,4-dione from allyl bromide that doesn't require a four-carbon reagent (like acetoacetate). Are there any other restrictions on the synthesis? For example, sometimes the question is posed that you are only allowed to use reagents with a certain number of carbons. $\endgroup$ – jerepierre Jun 4 '18 at 17:23
  • $\begingroup$ @jerepierre No, there are no 'limits'... I know, by adding acetoacetate I get one more carbon that I don't need. Unfortunately I didn't have another idea how to start the synthesis. $\endgroup$ – Netta Jun 4 '18 at 17:41
  • $\begingroup$ Treat your hexenone with Ozone and dimethyl sulfide to give 3-oxo-butanal (2), react this with Methyl Grignard to give the secondary alcohol (3) selectively over addition to the ketone. Oxidise this to acetoacetate. $\endgroup$ – Waylander Jun 4 '18 at 17:58
  • 1
    $\begingroup$ This begs the question, why would anyone want to make that dione? That's commercially available and cheaper from an atom economy perspective than the allyl bromide... The end game, as has been noted, is quite nice. $\endgroup$ – Zhe Jun 4 '18 at 18:40
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    $\begingroup$ I think merely to demonstrate a range of transformations,and get the student used to breaking a larger molecule down to accessible fragments. $\endgroup$ – Waylander Jun 4 '18 at 21:19

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