Question

The addition of $Br_2$ to (E) - but - 2 - ene gives

• A. (R, R) 2 - 3- dibromobutane
• B. (S, S) - 2 - 3 - dibromobutane
• C. (R, S) - 2 - 3 - dibromobutane
• D. a mixture of (R, R) and (S, S) 2, 3 dibromobutane

Answer 1

Answer: (C)

The addition of bromine to E- but-2-ene gives $( R , S )-2-3$ dibromobutane, it is always anti as bromine atoms added are on opposite sides.

In $( E )$ -but $-2$ -ene addition of $Br _{2}$ occurs as:



$( R , S )-2-3$ - dibromobutane.