Question

$C{H}_{3}C{H}_2-\underset{OH}{\underset{|}{\stackrel{Ph}{\stackrel{|}{C}}}}-\underset{OH}{\underset{|}{\stackrel{C{H}_3}{\stackrel{|}{C}}}-}C{H}_3$ $\underset{H_{2}O}{\overset{H_{2}S{O}_4}{\to }}$

Which carbonyl compound is the main product of the following rearrangement reaction?

• A. $C{H}_{3}C{H}_2-\underset{O}{\underset{||}{C}}-\underset{Ph}{\underset{|}{\stackrel{C{H}_3}{\stackrel{|}{C}}}}-C{H}_3$
• B. $Ph-\underset{O}{\underset{||}{C}}-\underset{C{H}_{2}C{H}_3}{\underset{|}{\stackrel{C{H}_3}{\stackrel{|}{C}}}}-C{H}_3$
• C. $C{H}_{3}C{H}_2-\underset{C{H}_3}{\underset{|}{\stackrel{Ph}{\stackrel{|}{C}}}-}\underset{O}{\underset{||}{C}}-C{H}_3$
• D. $C{H}_3-\underset{C{H}_3}{\underset{|}{\stackrel{Ph}{\stackrel{|}{C}}}}-\underset{O}{\underset{||}{C}}-C{H}_{2}C{H}_3$

Answer 1

The correct option is C $C{H}_{3}C{H}_2-\underset{C{H}_3}{\underset{|}{\stackrel{Ph}{\stackrel{|}{C}}}-}\underset{O}{\underset{||}{C}}-C{H}_3$

$C{H}_{3}C{H}_2-\underset{OH}{\underset{|}{\stackrel{Ph}{\stackrel{|}{C}}}}-\underset{OH}{\underset{|}{\stackrel{C{H}_3}{\stackrel{|}{C}}}-}C{H}_3$ $\underset{H_{2}O}{\overset{H_{2}S{O}_4}{\to }}$ $C{H}_{3}C{H}_2-\underset{C{H}_3}{\underset{|}{\stackrel{Ph}{\stackrel{|}{C}}}-}\underset{O}{\underset{||}{C}}-C{H}_3$

The carbonyl compound represented by the option (C) is the main product of the rearrangement reaction. This reaction is known as the pinacol–pinacolone rearrangement. In this reaction, a vicinal diol is converted to carbonyl compound.