Q.12. - Organic Chemistry

Question

Question: A key step in the synthesis of donepezil (trade name Aricept) is a directed aldol reaction that forms $\mathit{\alpha }\mathbf{,}\mathit{\beta }$-unsaturated carbonyl compound X. What carbonyl starting materials are needed to prepare X using a directed aldol reaction? What reagents are needed to convert X to donepezil?

Step-by-Step Solution

Answer

Answer

Step 1: Reduction reaction

Reduction reaction is the conversion of alkene into alkane under the reducing agent. The reducing agent used for such a reaction is ${\mathit{H}}_{\mathbf{2}}\mathbf{,}\mathbf{ }\mathit{P}\mathit{d}\mathbf{-}\mathit{C}$.

Step 2: Explanation of the reaction

The breaking of double bond results in the formation of aldehyde and ketone that are needed for the formation of X.

 

The aldehyde and ketone are shown below:

Aldehyde and ketone needed for X

 

The conversion of X to donepezil is done by $H_2, Pd-C$ ,as shown below:

Conversion of X to donepezil