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 $S$.
$2-S3-S$