2.3- dibromobutane meso compound isomer

Compounds that are achiral even though they have asymmetric carbon atoms are called meso compounds. The (2R,3S) isomer of 2,3-dibromobutane is a meso compound most meso compounds have this kind of symmetric structure, with two similar halves of the molecule having opposite configurations. In speaking of the two diastereomers of 2,3-dibromobutane, the symmetric one is called the meso diastereomer, and the chiral one is called the ( ) diastereomer, since one enantiomer is ( + ) and the other is (-). 

The reactant, too, exists as diastereomers a pair of geometric isomers. If we start with, say, ci5-2-butene, which of the stereoisomeric products do we get A mixture of all of them No. cw-2-Butene yields only racemic 2,3-dibromobutane none of the meso compound is obtained. A reaction that yields predominantly one stereoisomer (or one pair of enantiomers) of several diastereomeric possibilities is called a stereoselective reaction. 

---