How do I form the product with alkylation and condensation?

[Yokoko]

Homework Statement

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Relevant Equations

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I don't really know how to begin. I've done alkylations by having two of the same compounds react with each other e.g. two aldehydes but never started out with dimethyl malonate.

I was thinking I need 1,4 dibromobutane to form the cyclopentane ring but apart from that I'm clueless

 

[docnet]

Hi, it's been a few years since organic chemistry. But, since no one has commented on this post I'll try to help.

The reactant molecule has 3 carbons and the product has 6 carbons. Assuming one carbon atom will be lost through decarboxylation in the end, I think you are right we need 1,4 dibromobutane. There are two hydrogen atoms in the center carbon that can partake in enolate formation. After the first enolate alkylation, there is an intra-molecular enolate alkylation to form the ring. Given the reaction mechanism, there is only one plausible way this reaction would proceed.