MolSynapsequestion bank
MolSynapse / Question bank / General Organic Chemistry III: Reaction Intermediates / Kinetic vs thermodynamic enolate site on drawn ketones
JEE Main levelOne or more correct optionsDifficulty 2 of 3g3255

The ketone shown is converted into its enolate either with LDA at C or with sodium ethoxide in ethanol at C (equilibrating) and then methylated at carbon with methyl iodide. Which structures shown are major C-methylation products from the kinetic or from the thermodynamic enolate? Select all that apply.

  1. AStructure A
  2. BStructure B
  3. CStructure C
  4. DStructure D

Answer: A, C

The ketone shown is 2-methylcyclohexanone. The kinetic enolate (LDA, C) is formed at C6 and methylation gives 2,6-dimethylcyclohexanone. The thermodynamic enolate (more substituted, C1=C2) is methylated at C2 to give 2,2-dimethylcyclohexanone. The 2,5-dimethyl compound would need an enolate at C5, which is not alpha to the carbonyl, and the enol ether is an O-alkylation product, not a major one with methyl iodide.
Practice General Organic Chemistry III: Reaction Intermediates More on Kinetic vs thermodynamic enolate site on drawn ketones
Previous questionNext question

More questions on Kinetic vs thermodynamic enolate site on drawn ketones