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

Consider the following reaction sequence: 1,2-Dimethylcyclopentan-1-ol H₂SO₄, A [Zn/H₂O] O₃ B dil. NaOH, C The major product C is:

Options

  1. A1-Acetyl-2-methylcyclopentene
  2. B2,3-Dimethylcyclohex-2-en-1-one
  3. C5-Methylcyclohex-2-en-1-one
  4. D3-Methylcyclohex-2-en-1-one

Correct answer

D. 3-Methylcyclohex-2-en-1-one

Step-by-step solution

Step 1: Acid-catalyzed dehydration of 1,2-dimethylcyclopentan-1-ol proceeds via a tertiary carbocation. According to Saytzeff's rule, the most substituted alkene is formed as the major product, which is 1,2-dimethylcyclopentene. Step 2: Ozonolysis of 1,2-dimethylcyclopentene cleaves the tetrasubstituted double bond to yield a symmetrical diketone, heptane-2,6-dione ( CH₃-CO-CH₂-CH₂-CH₂-CO-CH₃ ). Step 3: Intramolecular aldol condensation of heptane-2,6-dione occurs in the presence of dilute NaOH. The enolate formed

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