Hilfe in Chemie?

Thus purely theoretically, in the first step, the bromine molecule polarized by the electron-rich double bond is added to the Br+ end and a three-ring with a bromoonium ion forms over the double bond.

The second bromine then acts nucleophilically on one of the two ring Cs and 1,2-dibromopentane is formed as the only reaction product. The bromide ion is preferably attacked at the point at which the more stable carbenium ion is formed after the ring opening, and this is definitely the secondary C, i.e. the C2. However, on the planar geometry of the three-ring or of the carbenium ion, the attack of Br- can take place either from above or from below. A chiral center is thus present at the C2. Since I do not see that one of these attacks would be sterically hindered by the propyl radical, I suspect that the R- and S-geometry, i.e. a racemate, is produced in equal parts. (RS)-1,2-dibromopentane is formed without the presence of Cl- ions. In the presence of Cl- there is a competitive situation of the nucleophiles Br- and Cl- about the carbenium ion on C2. It is therefore also formed, depending on the proportions of Br- and Cl-1-Br-2-Cl-pentane and probably also here as a racemic mixture of R and S. To a lower proportion I suspect the formation of (RS)-2-Br-1-Cl-pentane.

Without guarantee!