Question

which of the following compounds is meso? a. h3co2c - oh - oh - co2ch3 c. h3co2c - oh - co2ch3 b. h3co2c - oh - oh - co2ch3 d. h3co2c - oh - oh - co2ch3

Explanation:

Step1: Recall meso - compound definition

A meso - compound has chiral centers but is achiral overall due to an internal plane of symmetry.

Step2: Examine option A

It has a plane of symmetry passing through the middle carbon - carbon bond, making it meso. The two chiral centers have opposite configurations across the plane of symmetry.

Step3: Examine option B

There is no internal plane of symmetry, so it is not meso.

Step4: Examine option C

There is no internal plane of symmetry, so it is not meso.

Step5: Examine option D

There is no internal plane of symmetry, so it is not meso.

Answer:

A. $H_3CO_2C - \underset{OH}{\overset{H}{\underset{|}{\overset{|}{C}}}}-\underset{OH}{\overset{H}{\underset{|}{\overset{|}{C}}}}-CO_2CH_3$