Question

To prepare 3-ethylpentan-3-ol, the reactants needed are

• A. $C{H}_{3}C{H}_{2}MgBr+C{H}_{3}COC{H}_{2}C{H}_3$
• B. $C{H}_{3}MgBr+C{H}_{3}C{H}_{2}C{H}_{2}COC{H}_{2}C{H}_3$
• C. $C{H}_{3}C{H}_{2}MgBr+C{H}_{3}C{H}_{2}COC{H}_{2}C{H}_3$
• D. $C{H}_{3}C{H}_{2}C{H}_{2}MgBr+C{H}_{3}COC{H}_{2}C{H}_3$

Answer 1

The correct option is C $C{H}_{3}C{H}_{2}MgBr+C{H}_{3}C{H}_{2}COC{H}_{2}C{H}_3$

Grignard reagent react with ketones to form $3^{\circ }$ alcohol.
As $\text{3-ethylpentan-3-ol}$ is $3^{\circ }$ alcohol, so ketone is to be used for its preparation.All options have ketone and can give $3^{\circ }$ alcohol.
Option a) molecules yield 3-methylpentan-3-ol.
Option b) yields 3-methylhexan-3-ol.
Option d) yield 3-methylhexan-3-ol
But only c will give $\text{3-ethylpentan-3-ol}$ as shown in the reaction. Hence correct option is c.