Question

Which of the following compounds give Vic diol with Na/c2h5oh.

Answer 1

Explanation:

Step 1 - one electron transfer from sodium to carbonyl group:

Na⋅+RCH=O⟶Na++RCH⋅−O−

Step 2 - abstraction of a proton from ethanol:

CH3CH2OH+RCH⋅−O−↽−−⇀CH3CH2O−+RCH⋅−OH

This step is an equilibrium step, and is driven toward products by the second electron transfer (which consumes the RCH⋅−OH.

Step 3 - one electron transfer from a second sodium atom to the organic radical:

Na⋅+RCH⋅−OH⟶Na++RCH:−−OH

Step 4 - second proton transfer from ethanol:

CH3CH2OH+RCH:−−OH⟶CH3CH2O−+RCH2OH

This reaction, while technically an acid-base equilibrium, essentially goes to completion because of the vast disparity in acidity of C−H and O−H.

The net reaction is:

2Na+RCH=O+2CH3CH2OH⟶RCH2OH+2CH3CH2ONa