Convert hexane to 1,6-dibromohexane
In principle, alkanes may be converted to alkyl bromides by photoinitiated bromination. 

However, taking statistics (2 $\ce{CH3}$ vs 4 $\ce{CH2}$ groups) and stabilities of the radicals resulting from H abstraction by a bromine radical from your starting material into account, this approach is pretty worthless and will most likely yield 1,6-dibromohexane as a minor product in a complex mixture.

Consequently, your reasonable options are a) a different starting material (and a different synthesis) or b) simply buy 1,6-dibromohexane (around 20 Euro for 100 g).