Q24E - Organic Chemistry (Mcmurry)

Question

Predict the product (s) and provide the mechanism for each reaction below.

Step-by-Step Solution

Answer

The product prediction and its mechanism for each of the reaction can be explained.

Step 1: Production prediction and mechanism for (a)

The Grignard reagent’s nucleophilic addition of methylmagnesium bromide to nitrile group in o-methoxybenzonitrile and protonation of immine anion will give imine formation. The conversion of imine into amino alcohol. The nucleophilic attack of water follows the transfer of protons. The ammonia loss from amino alcohol in the last step leads to the production of o-methoxy acetophenone. The product are ammonia and o-methoxyacetophenone.

The formation mechanism can be denoted as,

 

Step 2: Production prediction and mechanism for (b)

The Grignard reagent’s nucleophilic addition of isopropyl magnesium bromide to nitrile group in 2-methylbutanenitrile and protonation of immine anion will give imine formation. The conversion of imine into amino alcohol. The nucleophilic attack of water follows the transfer of protons. The ammonia loss from amino alcohol in the last step leads to the production of 2,5-dimethylhexan-4-one. The product are ammonia and 2,5-dimethylhexan-4-one.

The formation mechanism can be denoted as,

Step 3: Production prediction and mechanism for (c)

The Grignard reagent’s nucleophilic addition of phenylmagnesium bromide to nitrile group in cyclopropanenitrile and protonation of immine anion will give imine formation. The conversion of imine into amino alcohol. The water’s nucleophilic attack follows the transfer of protons. The ammonia loss from amino alcohol in the last step leads to the production of cyclopropyl phenyl ketone. The product are ammonia and cyclopropyl phenyl ketone.

The formation mechanism can be denoted as,

Step 4: Production prediction and mechanism for (d)

The Grignard reagent’s nucleophilic addition of methylmagnesium bromide to nitrile group in 2-ethylbutanenitrile and protonation of immine anion will give imine formation. The conversion of imine into amino alcohol. The water’s nucleophilic attack follows the transfer of protons. The ammonia loss from amino alcohol in the last step leads to the production of 4-ethylhexan-3-one. The product are ammonia and 4-ethylhexan-3-one.

The formation mechanism can be denoted as,