Alkene Addition Reaction

Correct Answer: D

This is a halohydrin formation-type reaction. The addition of bromine in the presence of methanol leads to the addition of (-OMe) and (-Br) across the alkene such that the less substituted carbon gets the methoxy and the more substituted carbon gets the bromine. Moreover, the methoxy and the bromine are on opposite 3D faces of the molecule. When an alkene first reacts with bromine, it forms a bromonium ion intermediate that always gets attacked from the back (“Backside Attack”). The reason the nucleophile prefers the more substituted carbon is because that carbon is more partial positive and that C-Br bond length is longer+weaker in the bromonium ion! Finally, the (±) means racemic—you’re going to get a 50/50 mixture of the two enantiomeric molecules.