The major product (P) in the following reaction is : Ph- O \|C- O \|C-H [ ]KOH Major ProductP
- Ph- O \|C-COO K
- Ph- OH |CH-CH2OH
- Ph- OH |CH-COO K
- Ph- O \|C-CH2OH
Answer
(3) Ph- OH |CH-COO K
Solution
Phenylglyoxal, Ph-CO-CHO, has no α-hydrogen next to –CHO, so with concentrated alkali it undergoes an intramolecular Cannizzaro reaction.
OH adds to the aldehydic carbon; the hydride ion of this carbon shifts to the neighbouring keto carbon.
–CHO is oxidised to -COO and the keto group is reduced to -CH(OH)-
Ph-CO-CHO KOH, Ph-CH(OH)-COO K (potassium mandelate)
Answer: (3)