The bromination of trans-2-butene with in yields a set of stereoisomeric products. What is the total — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

The addition of halogens like $Br_2$ to an alkene proceeds via a cyclic halonium ion intermediate, resulting strictly in anti-addition. When anti-addition occurs on a symmetric trans-alkene (like trans-2-butene), the spatial arrangement leads to the formation of a meso compound. Specifically, meso-2,3-dibromobutane is formed. Because the meso compound contains an internal plane of symmetry, it is achiral and exists as a single stereoisomer. Therefore, the total number of stereoisomers obtained is 1.