[redballoons]

I've been stuck on this question for hours....

Outline a synthesis for pentylbenzene. You may start with benzene or aniline and any other compound containing no more than three carbon atoms.

Any suggestions?

[Dan]

Google "alkylation of benzene", attempt the question (this is a forum rule) and post what you come up with.

[orgo814]

How about starting with a 3 carbon alkyne? NaNH2 can remove the terminal hydrogen so the alkyne can react with something like ethyl bromide through substitution. Now, we have 2-pentyne. You can hydrogenate this with excess H2 to get it to be an alkane. With the alkane, perhaps a radical reaction? If you use Cl2 (heat and light) you won't get the primary halide as your major product, but you'll still get it in some form (maybe 45% vs its isomer... which would be 55%). After this, it's just a substitution reaction with benzene and the primary halide which im sure you were taught about in class.

[redballoons]

Sorry Dan... I didn't know the rules (I just joined today). I will make sure I read the rules before my next post.

Thank so much butlerw2!
I'm taking OChem II right now but it has been 3 years since I took OChem I. So I know how to do the substitution reactions with benzene but I couldn't figure out how to build the hydrocarbon chain.
Your post helped a lot and I think I can figure it out now

Thnx.

[orgopete]

This looks like a malonic acid problem combined with aromatic substitution.