Question

The absolute configuration of the following compound is :

• A. $2S,3R$
• B. $2S,3S$
• C. $2R,3S$
• D. $2R,3R$

Answer 1

Answer: (B)

An absolute configuration of a compound is the spatial arrangement of the atoms in a chiral molecule and its stereochemical description is termed as R or S, which refers to Rectus and Sinister, respectively.
At $C_2:$         At $C_3:$

Since least priority group is on horizontal position hence, R becomes S.
$\boxed{2-S}$            $\boxed{3-S}$