[boilerist]

I have been trying to synthesize the attached molecule.  I can start the synthesis from benzoic acid.  The benzoic acid  is a meta- director, which is where the alkyl group needs to be attached.  I have tried to use a Grignard reaction, a Friedel-Crafts reaction, and other methods but I can't get that chain to attach correctly.  Can anyone help me out?

[macman104]

I have been trying to synthesize the attached molecule.  I can start the synthesis from benzoic acid.  The benzoic acid  is a meta- director, which is where the alkyl group needs to be attached.  I have tried to use a Grignard reaction, a Friedel-Crafts reaction, and other methods but I can't get that chain to attach correctly.  Can anyone help me out?

Well, for the grignard, I'd imagine the acidic hydrogen would wreck that.  When you say you can't get the chain to attach correctly, what exactly does that mean?  Does it attach in a different position, does it attach with a rearrangement?

[boilerist]

i can attach a carbon chain but not the one i want i can get it to attach part way along the chain so the sturcture is wrong.

[sjb]

Does it have to be in one step?

You note that (I think) your carbon chain is rearranging if you try Friedel-Crafts alkylation.

Why not form an ester of the acid, doesn't really matter much what as long as it's not too hindered. Then Friedel-Crafts acylate with 2-methylbutanoyl chloride.

Now you have a ketone at C₃, but you can reduce that down to the methylene and saponify the ester under Wolff-Kishner (Huang-Minlon modification) conditions, then re-acidify on work-up to regenerate the acid.

S