Question

Which of the following pairs of compound can be used as starting material in the synthesis of $\text{2-phenyl-2-pentanol}$?

• A. $\text{PhBr and}C{H}_{3}C{H}_{2}C{H}_{2}COC{H}_3$
• B. $(C{H}_3{)}_{2}CHC{H}_{2}Br\text{and}PhCOC{H}_3$
• C. $C{H}_3(C{H}_2{)}_{2}C{H}_{2}Br\text{and}{C}_6{H}_{5}COOH$
• D. $\text{PhBr and}(C{H}_3{)}_{2}CHC{H}_{2}COC{H}_3$

Answer 1

The correct option is A $\text{PhBr and}C{H}_{3}C{H}_{2}C{H}_{2}COC{H}_3$

Grignard reagent react with formaldehyde to form $1^{\circ }$ alcohol.
Grignard reagent react with aldehyde except formaldehyde to form $2^{\circ }$ alcohol.
Grignard reagent react with ketone to form $3^{\circ }$ alcohol.
As $\text{2-phenylpentan-2-ol}$) is $3^{\circ }$ alcohol, so ketone is to be used for it preparation. All options have ketone and they give $3^{\circ }$ alcohol but only a will give $\text{2-phenylpentan-2-ol}$ as shown in the reaction. Hence correct option is a.