Question

The exposure of methyl isopropyl ketone to base generates two potential anionic products, X and Y. What are the two products? Which one is favored under conditions I and which is favored under conditions II? Why? Draw an energy diagram to help explain.

base xY solvent, T methyl isopropyl ketone Conditions I: MeONa, MeOH, room temperature Conditions ll: LDA, THF, -78°C

Answer 1

Answert Base Solvent T methant is obropy Ketone meona, meon room temperature (favoured) ( Thermodynamy cally stable) LDA, THE O -78 °C (favoured) Ekinetically stable)

Transition state * Transition state Energy ле istarting materials Thermodynamic kinchic control control Extent of reaction In the debrat anation of an unsymmetrical ketone, the kinetic product is the eno late resulting removal from while of the most accessible 2-4 the thermodynamic product has more the highly sutati tuted enodate. use of low temperature and stericale Hirdexed base (LDA, -78°() increase the kineric selectivity whereas high temperature and stexically unhindered tase (meona, 8t) increase the thermodynamic selectivity.