Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE MainChemistryAldehydes and Ketones

An aliphatic ketone X undergoes reaction with NaCN followed by heating with ethanol and acid ( H ₃ O ^ ) to yield an intermediate Y. Compound Y reacts with excess methylmagnesium bromide ( MeMgBr ) followed by acidic workup to give 3-ethyl-2-methylpentane-2,3-diol as the major product. Identify the IUPAC names of starting ketone X and intermediate Y.

Options

  1. AX = Propanone ; Y = Ethyl 2-hydroxy-2-methylpropanoate
  2. BX = Pentan-2-one ; Y = Ethyl 2-hydroxy-2-methylpentanoate
  3. CX = Pentan-3-one ; Y = Ethyl 2-ethyl-2-hydroxybutanoate
  4. DX = Pentan-3-one ; Y = 2-Ethyl-2-hydroxybutanoic acid

Correct answer

C. X = Pentan-3-one ; Y = Ethyl 2-ethyl-2-hydroxybutanoate

Step-by-step solution

The final product is 3-ethyl-2-methylpentane-2,3-diol, which has the structure CH ₃ CH ₂- C ( OH )( CH ₂ CH ₃)- C ( OH )( CH ₃)₂ . This diol is formed by the reaction of an ester with excess methylmagnesium bromide ( MeMgBr ). The - C ( OH )( CH ₃)₂ fragment is generated when the ester group reacts with two equivalents of MeMgBr . The remaining fragment, CH ₃ CH ₂- C ( OH )( CH ₂ CH ₃)- , must have originated from the initial ketone X. This indicates that ketone X is pentan-3-one ( CH ₃ CH ₂ COCH ₂ CH ₃ ). Reaction

Practice Aldehydes and Ketones on Quantrex Academy →

More from Aldehydes and Ketones

Consider the following reaction. The major product (P) formed is: 2026' x ' is the product which is obtained from benzene by reacting it with carbon monoxide and hydrogen chloride in the presence of cuprous chloride. ' y ' is the major product obtain 2026' x ' is the product which is obtained by the hydrolysis of prop-1-yne in the presence of mercuric sulphate under dilute acidic medium at 333 K. ' y ' is the product which is obtai 2026Given below are two statements: Statement-I: The condensation reaction between CH₃-CH=O and under optimum pH will produce . Statement-II: The molecule will generate Ph-CH=O in the 2026An organic compound " x " where molar ratio of C, O and H are equal, on treatment with 50 % KOH under reflux followed by acidification produced " y ". The most likely structure of 2026Given below are the four isomeric compounds ( P , Q , R , S ) Identify correct statements from below. A. Q , R and S will give precipitate with 2,4- DNP . B. P and Q will give posi 2026Given below are two statements: Statement I : Cross aldol condensation between two different aldehydes will always produce four different products. Statement II : When semicarbazid 2026Which of the following statements are TRUE about Haloform reaction?: A. Sodium hypochlorite reacts with KI to give KOI. B. KOI is a reducing agent. C. , -unsaturated methylketone ( 2026 Full Aldehydes and Ketones list All JEE Main PYQs