p-cresol reacts with chloroform in alkaline medium to give the compound A which adds hydrogen cyanide to form, the compound B. The latter on acidic hydrolysis gives chiral carboxylic acid. The structure of the carboxylic acid is
(A)(see structure)
(B)(see structure)
(C)(see structure)
(D)(see structure)✓ Correct
Answer: (D)
Solution
The sequence is a Reimer-Tiemann reaction followed by cyanohydrin chemistry. p-Cresol treated with chloroform in alkali picks up a −CHO group ortho to the phenolic −OH, giving a hydroxy-substituted methylbenzaldehyde as the first compound. Adding HCN across that aldehyde builds a cyanohydrin, and acidic hydrolysis then turns the −CN into −COOH. The carbon now carrying −OH, −COOH, a hydrogen and the aryl group holds four different groups, so the resulting carboxylic acid is chiral, matching the structure drawn with the −CH(OH)COOH group placed ortho on the cresol ring.
JEE Main · 2005 · 08 May 2005 · Offline · Single correct option
