The aldehyde shown is treated with Tollens' reagent; the resulting carboxylate is treated with NaBH4 in water, and the mixture is then acidified and warmed. Which structure is the final organic product?

MolSynapse / Question bank / Aldehydes, Ketones and Carboxylic Acids / Reduction, oxidation and HVZ products of drawn carbonyls and acids

JEE Advanced levelSingle correct optionDifficulty 3 of 3co259

The aldehyde shown is treated with Tollens' reagent; the resulting carboxylate is treated with $NaBH X_{4}$ in water, and the mixture is then acidified and warmed. Which structure is the final organic product?

AStructure A
BStructure B
CStructure C
DStructure D

Answer: A

The drawn compound is 4-oxopentanal. Tollens' reagent oxidises only the CHO to carboxylate (ketone untouched); NaBH4 reduces the ketone but not the carboxylate, giving 4-hydroxypentanoate. On acidification and warming, the gamma-hydroxy acid closes to the five-membered lactone, gamma-valerolactone. B needs reduction of the acid, C stops after step 1.

Practice Aldehydes, Ketones and Carboxylic Acids More on Reduction, oxidation and HVZ products of drawn carbonyls and acids

Previous questionNext question

The aldehyde shown is treated with Tollens' reagent; the resulting carboxylate is treated with NaBHX4​ in water, and the mixture is then acidified and warmed. Which structure is the final organic product?

Answer: A

More questions on Reduction, oxidation and HVZ products of drawn carbonyls and acids

The aldehyde shown is treated with Tollens' reagent; the resulting carboxylate is treated with $NaBH X_{4}$ in water, and the mixture is then acidified and warmed. Which structure is the final organic product?