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Synthesis Problem

I am working on this synthesis problem. My first step was converting the dienophile given into a diene via E2 elimination. From the product given, I concluded that the dienophile will carry the double bonded oxygen. I think I understand how to draw the Diels Alder reaction. However, I am stuck on how to generate the carbon chain from the two wedges. I appreciate any help or hints.

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    $\begingroup$ This is not just one step Diels Alder reaction. It is a multi-steps synthetic problem. Al least, you can approach by retro-synthetic steps to find out the diene and dienophile. $\endgroup$ Jan 30 at 23:31
  • $\begingroup$ @MathewMahindaratne Yes i know that. But please read my description to see what Im confused about. $\endgroup$ Jan 30 at 23:41
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    $\begingroup$ Your text is not very clear. You conclude that the dienophile will have the doubly bonded oxygen --- which? There are four doubly bonded oxygens in the product. What E2 elimination are you talking about? There isn't any functional group that can be eliminated from the starting molecule. It's not possible to deduce this from the description you gave. If you can draw a diagram to show your suggested reaction scheme, that will help greatly. $\endgroup$
    – orthocresol
    Jan 31 at 0:00

1 Answer 1

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Conceptually, you may think about the right hand hemisphere of the target molecule as derived from butane-1,4-diol:

enter image description here

You would use its bis-enolate as substrate for a Diels-Alder reaction with a (Z)-configurated dienophile. This aims to install R' and R'' on the same side of the cyclohexene built (cis relationship). There would be multiple functional group interconversions (FGI); reduction of the double bond in the cyclohexene, cleavage of the ether groups, oxidation of the then revealed 1,4-diol into a 1,4-dione (without tapping into an analogue of the redox couple of hydroquinone / benzoquinone).

The diene exhibits a pattern of six carbon atoms between the two carbonyl-C, thus on paper one way to disconnect this one were an ozonolyis (reductive workup):

enter image description here

A bibliographic search should query for examples where the triple substituted diene reacts faster than the double substituted. One plausible access to the diene (to perform the ozonolysis) could be the Birch reduction of toluene.

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