question_answer

Claisen condensation is not given by

A)

B)

C)

D)  

Correct Answer: A

Solution :

Key Idea In Claisen condensation aromatic aldehydes having no a-hydrogen atom react with aldehyde, ketones or esters having \[\alpha -\]hydrogen atom in presence of dilute alkali to form \[\alpha ,\beta -\]unsaturated carbonyl compound. eg,          \[C{{H}_{6}}{{H}_{5}}CHO+{{H}_{2}}\overset{C{{H}_{3}}}{\mathop{\overset{|}{\mathop{C}}\,}}\,-COO\] \[\,\xrightarrow{\text{dil}\,\text{NaOH}}\] \[\alpha ,\beta -\]unsaturated carbonyl. Compound Claisen condensation is not given by as it does not contain \[\alpha -\]hydrogen atom.