Which of the following compounds may posses a meso stereosiemer?

Options

A. `CH_(3)CHCICHBrCHCICH_(3)`
B. `CICH_(2)CHBrCH_(2)CI`
C. `BrCH_(2)CHCICH_(2)CI`
D. `CH_(3)CHBrCHCICHCICH_(3)`

Answer

A

Explanation

A meso compound must have at least one pair of identical sterocenters. The compound
`CH_(3)-overset(**)underset(CI)underset(|)(CH)-underset(Br)underset(|)(CH)-overset(**)underset(CI)underset(|)(CH)-CH_(3)`
has two chiral carbons but the four liagands bonded to one chiral carbon atom `(CH_(3),H,CI`and `-CHBrCHICH_(3))` are the same as those bonded to the second chiral carbon. A meso compound is chiral because at least one conformer has either a plane or a point (centre) of symmetry which makes it superposable upon its mirror image.