Question

Which carbonyl compounds do not undergo an aldol reaction when treated with −oh in h2o? select all that apply?

Answer 1

Answers:
              Among many few compounds are shown below which can not undergo Aldol Condensation reactions.

Explanation:
                   Aldol Condensation reactions are given by those carbonyl compounds which are capable of forming conjugate bases called as Enolates. Enolates are formed when carbonyl compounds having hydrogen atoms at alpha position are treated with strong bases. This hydrogen atom at alpha position is mildly acidic in nature and readily donated to base as the upcoming conjugate base i.e. has stability due to resonance. 
                  So those carbonyl compounds which lacks these acidic protons at alpha position are not able to form enolates, Hence, unable to undergo Aldol Condensation reactions. Few examples are attached below,