[girl101]

i have F + conc H₂SO₄ = propylbenzenesulfonic acid

propylbenzenesulphonic acid +br₂/fe₂br₃ = bromopropylbenzsulphonic acid G

when that reacts with steam and h2so4 it goes to  H bromobenzenepropyl then that reacts with kmno4 to get bromobenzoic acid

part b im not sure but i discussed opm directors

see attached file thankyou

[AWK]

Your problem has nothing common with retrosynthesis. You are doing electrophillic aromatic substitution with using directional effect of substituent groups. Every textbook of organic chemistry treats this problem.

fe2br3

[girl101]

well the lecturer's area is retrosynthesis . and retrosynthesis is working backward my other questions were based on retrosynthesis .

[orgopete]

Hint, iron is a reductant. What do you think might be an intermediate that can allow a new substitution at C-4?

[girl101]

 i thought the lecturer meant febr3 since br2 isnt strong enough to react with the ring we use the lewis acid form. since its fe would it reduce the propyl to propene , benzene to cyclohexane ? im confused

[orgopete]

I'm at a disadvantage as I wasn't in the class nor read your textbook so it is difficult for me to know what reactions you should know or will find in your textbook. However, as I read the question, you have correctly identified the route to 1-bromo-2-propylbenzene. It requires different reagents to arrive at p-bromopropylbenzene. In this case iron is being used. It is a reductant. I suggest if you were to know the answer to this question, then you should have been taught this reaction or can find it in your textbook. I believe the product of that reduction can react with bromine to give the bromopropylbenzene product. Let's see if that helps.