Question

Identify the number of stereoisomers that can be formed from the compound 2,3-dichlorobutane, and draw their structures.

Answer 1

2,3-dichlorobutane has two chiral centers, which are carbons 2 and 3. To determine the number of stereoisomers, we can use the formula 2^n, where n is the number of chiral centers. In this case, n = 2, so there are 2^2 = 4 possible stereoisomers.Here are the structures of the four stereoisomers:1.  2R,3R -2,3-dichlorobutane:      Cl      Cl       |       |H3C - C - C - C - CH3       |       |       H       H2.  2S,3S -2,3-dichlorobutane:      Cl      Cl       |       |H3C - C - C - C - CH3       |       |       H       H3.  2R,3S -2,3-dichlorobutane:      Cl      H       |       |H3C - C - C - C - CH3       |       |       H       Cl4.  2S,3R -2,3-dichlorobutane:      Cl      H       |       |H3C - C - C - C - CH3       |       |       H       ClThese four stereoisomers include two pairs of enantiomers:  2R,3R  and  2S,3S , and  2R,3S  and  2S,3R .