Which of the following on reaction with Grignards reagent followed by hydrolysis forms tertiary alcohol?
Which of the following on reaction with Grignards reagent followed by hydrolysis forms tertiary alcohol?
Methanal
Ethanal
Propanal
Propanone
Solution
Grignard reagents react with carbonyl compounds followed by hydrolysis to yield alcohols, with the alcohol type determined by the carbonyl substrate.
Methanal produces primary alcohols:
\(\mathrm{RMgX}+\mathrm{HCHO} \xrightarrow{\text { 1. Ether, 2. } \mathrm{H}_3 \mathrm{O}+} \mathrm{R}-\mathrm{CH}_2-\mathrm{OH}\)
Aldehydes other than methanal yield secondary alcohols:
\(\mathrm{RMgX}+\mathrm{R}^{\prime}-\mathrm{CHO} \xrightarrow{\text { 1. Ether, 2. } \mathrm{H}_3 \mathrm{O}+} \mathrm{R}-\mathrm{CH}\left(\mathrm{R}^{\prime}\right)-\mathrm{OH}\)
Ketones form tertiary alcohols:
\(\mathrm{RMgX}+\mathrm{R}^{\prime} 2 \mathrm{C}=\mathrm{O} \xrightarrow{\text { 1. Ether, 2. } \mathrm{H}_3 \mathrm{O}+} \mathrm{R}-\mathrm{CR}_2^{\prime}-\mathrm{OH}\)
Among the options, propanone is a ketone and thus produces a tertiary alcohol.