[mizna.z]

Only allowed to use molecules that are 3 or less carbons to make the attached molecule. So I've started making this molecule and im stuck.
I started with propane.

Propane + Br2 + light --> bromopropane---> Mg, ether---> grignard + propanal + Hcl --> Ch3CH2CH(Ch3)OH---> PBr3 --> CH3CH2CH(CH3)Br....
added more Br, then NaOH +H20 to get  BrCH(OH)CH(Ch3)Br--> PCC--> BrC=OCH(Ch3)Br + Ch3Ch2Ch2MgBr + Hcl--->  see 2nd molecule attached.

and now im stuck.

i have a feeling theres an easier/simpler way to do this and i cant think of it. and if someone could help to get the last CH3CH2 on there and replace the H (red) to a CH3, that would be awesome!

[spirochete]

I didn't follow your synthesis completely, I think you may have lost track of some carbons follwing the grignard addition.  With the 3 carbon limit it is difficult to figure out how to tack on that last carbon, but I figured out a way to do it that exploits the symmetry of the product.

I'll tell you the beginning and end and see if you can figure out the middle part.  I've told you or hinted at every reaction I used.

In my retrosynthesis I "started" with bromination of a pi bond.  That's what jumps out at me when I see two adjacent (geminal) halogens.  Then you have a pi bond which can be made with either a wittig reaction or grignard addition followed by dehydration.  Both would come from a ketone of course.

On the other end of things I start out with acetone as my first reactant.  In between, in some order I brominate the alpha positions on acetone (do we want acid or base conditions?), and add a carbon nucleophile/s to a protected acetone.  Acetone and the final product both have similar symmetry and a couple of these reactions exploit that.

I may have used some reactions you don't know, where are you in orgo right now?