in the reaction between PhCHO and tBuCHO in basic medium which one will convert into Na salt of carbozylic acid and why???
PhCHO will convert into Na salt of carboxylic acid and t-BuCHO will convert into alcohol.
Explanation-
First step of cannizzaro reaction involve the attack of hydroxyl group at the carbonyl carbon i.e OH- a nucleophile attacks at electrophilic centre i.e carbonyl carbon. Thus, higher the positive charge on the carbonyl carbon more strongly the first step will proceed and product formation takes place according to that only. Out of benzaldehyde and tertiary butanal the attack of nucleophile occurs at benzaldehyde because + I effect (inductive effect ) of Alkyl group in butanal tends to decrease the + charge on the carbonyl carbon or decreases the electrophilicty of the carbonyl carbon due to which hydroxyl group will attack the benzaldehyde carbonyl carbon first and Na salt of carboxylic acid is formed from benzaldehyde whereas t-BuCHO will convert into alcohol.
Note- This decrease in the + charge on the carbonyl carbon is due to +I of alkyl groups in butanal as shown below
Explanation-
First step of cannizzaro reaction involve the attack of hydroxyl group at the carbonyl carbon i.e OH- a nucleophile attacks at electrophilic centre i.e carbonyl carbon. Thus, higher the positive charge on the carbonyl carbon more strongly the first step will proceed and product formation takes place according to that only. Out of benzaldehyde and tertiary butanal the attack of nucleophile occurs at benzaldehyde because + I effect (inductive effect ) of Alkyl group in butanal tends to decrease the + charge on the carbonyl carbon or decreases the electrophilicty of the carbonyl carbon due to which hydroxyl group will attack the benzaldehyde carbonyl carbon first and Na salt of carboxylic acid is formed from benzaldehyde whereas t-BuCHO will convert into alcohol.
Note- This decrease in the + charge on the carbonyl carbon is due to +I of alkyl groups in butanal as shown below
