Phenol reacts with methyl chloroformate in the presence of NaOH to form product A. A reacts with Br2 to form product B. A and B are respectively :
(A)(see structures)A
(B)(see structures)AB
(C)(see structures)
(D)(see structures)AB✓ Correct
Answer: (D)
Solution
Phenol first loses its acidic proton to NaOH, and the phenoxide then attacks the carbonyl carbon of methyl chloroformate, displacing chloride; this esterification gives phenyl methyl carbonate, CX6HX5−O−CO−O−CHX3, as product A. The carbonate group still releases some electron density into the ring but is only weakly activating, so when A meets BrX2 the electrophilic substitution occurs at the less hindered para position, giving the para-bromo carbonate as product B.
JEE Main · 2018 · 08 Apr 2018 · Offline · Single correct option