Question

Cis-3-hexene $\stackrel{\left(a\right)}{\to }$ meso 3,4-hexanediol
trans-3-hexene $\stackrel{\left(b\right)}{\to }$ meso 3,4-hexanediol.
Choose pair of reagent (a, b) for above conversions.

• A. Cold $KMn{O}_4,Os{O}_4$
• B. Cold $KMn{O}_4,RC{O}_{3}H/H_3{O}^{⨁}$
• C. $RC{O}_{3}H/H_3{O}^{⨁},coldKMn{O}_4$
• D. None of these

Answer 1

The correct option is B Cold $KMn{O}_4,RC{O}_{3}H/H_3{O}^{⨁}$

$Cis-3-Hexane\underrightarrow{ColdKMn{O}_4}Meso-3-4-hexaanediol$

This is because syn addition to a cis molecule results in a meso compound and cold ${KMnO}_4$ is a syn reagent.

$Trans-3-hexane\underrightarrow{RC{O}_{3}H/H_3{O}^{+}}Meso-3-4-hexanediol$

Similarly anti addition to trans molecule forms meso compound