[jedy567]

Question:  what would be the major product obtained from the reaction of Br2 with 1-butene if the reaction were carried out in:

a) dichloromethane?
b) ethyl alcohol

For letter a, we have one Br atom acting as the electrophile, forming the bromonium intermediate.  However, since the solvent is much more concentrated, I feel like the Cl atoms on the dichloromethane could act as the nucleophile, and since there are more of those molecules than of bromide anions, shouldn't they take precedence and form as the major product?

The answer to this question is listed as a vicinal (1,2) addition of Br.  I don't understand why this is the correct over the reasoning above.

[kamiyu]

I strongly suggest you consult the Internet or textbook

1) The chlorine in DCM is seldom reactive. It can be reactive, but in rare cases. Examples such as reaction with Na metal or SN2 reaction with triethylamine.

2) Think about the reaction of the intermediate when there is something hydroxylic (i.e. contain OH groups)

Good luck