Question

34. For the given reaction, the product is

Answer 1

The product is 4‑chloro‑4′‑(4‑chlorobenzoyl)benzophenone.

Answer 2

The reaction involves an 18O‐labeled diaryl ketone (a benzophenone in which one benzene ring is substituted by –Cl and the carbonyl oxygen is 18O‐labeled) reacting with a 4‑chlorobenzoic acid. Under the reaction conditions the benzoic acid is converted into an acylium ion (losing CO₂), which then electrophilically attacks the benzophenone. The more activated (unsubstituted) ring of the benzophenone is substituted preferentially at its para position. Thus the acyl (4‑chlorobenzoyl) group becomes attached para to the carbonyl on that ring. Notice that the 18O label remains with the original carbonyl carbon of the benzophenone moiety.